We have followed the Matrix and Ancient Valley approach of having characters and animations facing Y+, and then rotating the character mesh component in the character blueprint towards X+ which is game forward.
This seems to be a good solution, until we have discovered that for root motion to work, animations have to be facing X+ in the first frame. So now we have characters facing Y+ and animations X+, and when they spawn, we can see a one frame glitch rotation of 90 degrees.
I think that now we have to rotate characters 90 degrees towards X+ but I was wondering, first why we have this contradiction, and second if rotating characters 90 degrees on import is the best way to fix it.