When used as part of the fast path in an ABP, variable Blueprint Getters are not used. If something with a getter that does not conform to or is supported by fast path, is used then fast path should be disabled.
Create a C++ class from a UAnimInstance
Add two UAnimSequence variables.
Create and assign a BlueprintGetter function for the first variable that returns the second.
Create an ABP from the C++ class, and assign two different UAnimSequences to the variables.
In the AnimGraph, play the first sequence and in the event graph print its name.
Result: The first sequence is played(fast path) and the second sequence is printed
Expected: The second sequence is played and printed
Nativeize the ABP and recompile it.
Result: The second sequence(non fast-path) is played and printed
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-87380 in the post.