There is an issue with Actor Variable References that become settable when in type array in the Level blueprint. Once in the array, the actor can be successfully addressed, however using the Save Current Level as and saving as a new level deletes the reference in the element upon opening of the new level. It is unknown if this is intended behavior or not. This issue does not appear to be a regression.
Versions Tested: Issue occurs in all versions tested
4.16.3 - CL: 3561208
4.17.2 - CL: 3658906
4.18.0 - CL: 3709383
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-52324 in the post.