Could this be the problem?
*Engine Bug Workaround Fix*
- Set Master Pose node on EquipmentCharacter's MainHand and OffHand Skeletal meshes can cause some imported art to flicker and disappear when attached to sockets.
Spoiler:
[EquipmentCharacter]
- Simply remove the Set Master Pose node at the end of the logic in the OnRep_MainHandMesh() and OnRep_OffHandMesh() functions.
(It's really not needed on skeletal meshes that get attached to a socket. It's for syncing meshes to the same animation BP so they animate in sync but never caused issues in earlier engine versions)