OnRep functions do not fire on the Server when elements are added to an array variable marked as RepNotify

OnRep functions do not fire on the Server when elements are added to an array variable marked as RepNotify. They do not fire at all when setting an array element with the Set Array Elem node.

Probably related to [Link Removed].

Reproduced in 4.7.2 and 4.7.3 binary and Main (//depot/UE4/Promotable-CL-2479729)

1. Download the test project (See Comments)
2. Open the FirstPersonCharacter Blueprint
3. PIE

Result:
OnRep_Guns never fires the print string on the Server.