RepNotify without info about starting time will cause the montage to be out of sync fairly often.
e.g. Reload montage is 2 seconds long.
Player #1 starts reloading 10 seconds into game.
The delay of sending montage request to server and then to player #2 means that for player #2, the montage starts playing 11 seconds into game.
Montage for player #1 finishes at 12 seconds.
Montage for player #2 finishes at 13 seconds.
With custom struct/event, when the montage started playing, what section it is in, what section it should be in next etc is included.
Then it doesn’t matter when the next player gets it, it’ll play from the correct point in the montage and end at the correct time.
A multi-cast has the same issue as a rep notify, except anyone who is not relevant when the multi-cast is called doesn’t see anything if they become relevant shortly there after.
This is fine with short, quick non-gameplay relevant animations, but for something like a reload etc, not so much 