diff --git a/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.test.ts b/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.test.ts
deleted file mode 100644
index 50a6084dafa6..000000000000
--- a/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.test.ts
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { Filter } from '../filters';
-import { customFilterMatchesIndex } from './custom_filter_matches_index';
-import { IIndexPattern } from '../../index_patterns';
-
-describe('customFilterMatchesIndex', () => {
-  it('should return true if the custom filter has no meta', () => {
-    const filter = {} as Filter;
-    const indexPattern = { id: 'foo', fields: [{ name: 'bar' }] } as IIndexPattern;
-
-    expect(customFilterMatchesIndex(filter, indexPattern)).toBe(true);
-  });
-
-  it('should return true if no index pattern is passed', () => {
-    const filter = { meta: { index: 'foo', key: 'bar', type: 'custom' } } as Filter;
-
-    expect(customFilterMatchesIndex(filter, undefined)).toBe(true);
-  });
-
-  it('should return true if the custom filter has meta without a key', () => {
-    const filter = { meta: { index: 'foo', type: 'custom' } } as Filter;
-    const indexPattern = { id: 'foo', fields: [{ name: 'bar' }] } as IIndexPattern;
-
-    expect(customFilterMatchesIndex(filter, indexPattern)).toBe(true);
-  });
-
-  it('should return false if the filter is not custom', () => {
-    const filter = { meta: { index: 'foo', key: 'bar', type: 'match_all' } } as Filter;
-    const indexPattern = { id: 'foo', fields: [{ name: 'bar' }] } as IIndexPattern;
-
-    expect(customFilterMatchesIndex(filter, indexPattern)).toBe(false);
-  });
-
-  it('should return false if the custom filter is a different index id', () => {
-    const filter = { meta: { index: 'foo', key: 'bar', type: 'custom' } } as Filter;
-    const indexPattern = { id: 'bar', fields: [{ name: 'foo' }] } as IIndexPattern;
-
-    expect(customFilterMatchesIndex(filter, indexPattern)).toBe(false);
-  });
-
-  it('should return true if the custom filter is the same index id', () => {
-    const filter = { meta: { index: 'foo', key: 'bar', type: 'custom' } } as Filter;
-    const indexPattern = { id: 'foo', fields: [{ name: 'barf' }] } as IIndexPattern;
-
-    expect(customFilterMatchesIndex(filter, indexPattern)).toBe(true);
-  });
-});
diff --git a/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.ts b/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.ts
deleted file mode 100644
index c98f6d1575a1..000000000000
--- a/src/plugins/data/common/opensearch_query/opensearch_query/custom_filter_matches_index.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { IIndexPattern } from '../../index_patterns';
-import { Filter } from '../filters';
-
-export function customFilterMatchesIndex(filter: Filter, indexPattern?: IIndexPattern | null) {
-  if (!filter.meta?.key || !indexPattern) {
-    return true;
-  }
-  if (filter.meta?.type !== 'custom') {
-    return false;
-  }
-  return filter.meta.index === indexPattern.id;
-}
diff --git a/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.test.ts b/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.test.ts
index f610b1e7179f..ad68e14b2c54 100644
--- a/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.test.ts
+++ b/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.test.ts
@@ -66,4 +66,18 @@ describe('filterMatchesIndex', () => {
 
     expect(filterMatchesIndex(filter, indexPattern)).toBe(true);
   });
+
+  it('should return false if the custom filter is a different index id', () => {
+    const filter = { meta: { index: 'foo', key: 'bar', type: 'custom' } } as Filter;
+    const indexPattern = { id: 'bar', fields: [{ name: 'foo' }] } as IIndexPattern;
+
+    expect(filterMatchesIndex(filter, indexPattern)).toBe(false);
+  });
+
+  it('should return true if the custom filter is the same index id', () => {
+    const filter = { meta: { index: 'foo', key: 'bar', type: 'custom' } } as Filter;
+    const indexPattern = { id: 'foo', fields: [{ name: 'barf' }] } as IIndexPattern;
+
+    expect(filterMatchesIndex(filter, indexPattern)).toBe(true);
+  });
 });
diff --git a/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.ts b/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.ts
index f8c2ab67ee95..529e68609aeb 100644
--- a/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.ts
+++ b/src/plugins/data/common/opensearch_query/opensearch_query/filter_matches_index.ts
@@ -31,14 +31,14 @@
 import { IIndexPattern, IFieldType } from '../../index_patterns';
 import { Filter } from '../filters';
 
-/*
- * TODO: We should base this on something better than `filter.meta.key`. We should probably modify
- * this to check if `filter.meta.index` matches `indexPattern.id` instead, but that's a breaking
- * change.
- */
 export function filterMatchesIndex(filter: Filter, indexPattern?: IIndexPattern | null) {
   if (!filter.meta?.key || !indexPattern) {
     return true;
   }
+
+  if (filter.meta?.type === 'custom') {
+    return filter.meta.index === indexPattern.id;
+  }
+
   return indexPattern.fields.some((field: IFieldType) => field.name === filter.meta.key);
 }
diff --git a/src/plugins/data/common/opensearch_query/opensearch_query/from_filters.ts b/src/plugins/data/common/opensearch_query/opensearch_query/from_filters.ts
index e7b13f5a10d6..990dca144abf 100644
--- a/src/plugins/data/common/opensearch_query/opensearch_query/from_filters.ts
+++ b/src/plugins/data/common/opensearch_query/opensearch_query/from_filters.ts
@@ -34,7 +34,6 @@ import { filterMatchesIndex } from './filter_matches_index';
 import { Filter, cleanFilter, isFilterDisabled } from '../filters';
 import { IIndexPattern } from '../../index_patterns';
 import { handleNestedFilter } from './handle_nested_filter';
-import { customFilterMatchesIndex } from './custom_filter_matches_index';
 
 /**
  * Create a filter that can be reversed for filters with negate set
@@ -77,10 +76,7 @@ export const buildQueryFromFilters = (
     return filters
       .filter(filterNegate(negate))
       .filter(
-        (filter) =>
-          !ignoreFilterIfFieldNotInIndex ||
-          filterMatchesIndex(filter, indexPattern) ||
-          customFilterMatchesIndex(filter, indexPattern)
+        (filter) => !ignoreFilterIfFieldNotInIndex || filterMatchesIndex(filter, indexPattern)
       )
       .map((filter) => {
         return migrateFilter(filter, indexPattern);