diff --git a/src/sage/groups/perm_gps/partn_ref/data_structures.pxd b/src/sage/groups/perm_gps/partn_ref/data_structures.pxd
index ecf244607d1..1cbb95231d5 100644
--- a/src/sage/groups/perm_gps/partn_ref/data_structures.pxd
+++ b/src/sage/groups/perm_gps/partn_ref/data_structures.pxd
@@ -14,6 +14,8 @@ from libc.string cimport memcpy
 from libc.stdlib cimport rand
 from sage.libs.gmp.mpz cimport *
 
+from cysignals.memory cimport sig_free
+
 
 cdef enum:
     # The following is for the automorphism group computation, says what the
@@ -162,6 +164,8 @@ cdef inline void OP_make_set(OrbitPartition *OP) noexcept:
     new_mcr[n] = n
     new_size[n] = 1
 
+    sig_free(OP.parent)
+
     OP.parent = new_parent
     OP.rank = new_rank
     OP.mcr = new_mcr