Do we not need to limit the size of this cache?

I think the map here will be limited to the size of the AttributeType (which was in the current class - maybe we should change the name). I tried an alternate version which used a switch statement on the enum and individual boolean variables, but it did not seem to impact the timing w/JMH. I will confirm the timing again - and we can also update to have a switch statement and explicit boolean results.

An approach with a switch statement and primitive boolean variables was slightly quicker on second pass. I updated the logic, please let me know if we should evaluate the previous approach.

Discussed additional performance ideas, going to run additional tests.

Are we actually calling all these pairs?

You are iterating over an array of arrays but there's only 1 inner array with 12 elements in it.
It seems like we want 6 inner arrays, each with two elements {action, verify}
I think we're actually only testing the isIndexOnlyField pair here.

It also has me wondering if maybe it's just easier to do the manual calls in the test instead of dealing with all the method references and such.

cachedHelper.isIndexOnlyField(fieldName);
verify(mockHelper).isIndexOnlyField(fieldName);

cachedHelper.isIndexedField(fieldName);
verify(mockHelper).isIndexedField(fieldName);

// ...

That is a bug, thank you for catching that. In regards to the manual tests - I updated, thank you.