This is probably just a cosmetic glitch, but to make UE perfect, here you go
- in Animation BP
- animation graph
- state machine
- custom blend logic
- edit blend graph
- “Get Source State Pose” and “Get Destination State Pose”
- Evaluator Mode, change it to “Delayed Freeze”
- this will result in appearance of the 2nd and same property “Frames to Cache Pose”
While Evaluator Mode is set to Freeze or Standard, property “Frames to Cache Pose” is still visible, but only once, only changing to Delayed Freeze will cause the property to duplicate.
The duplicated property seems to be sort of an instance of the first version because when you change one value, the other changes in realtime to the same value.
Engine version 4.6.1