No idea if it's a bug, for me is definitely an unexpected behaviour:
Basically I control the Symbol timeline from outside and in the end I reverse the direction, but when reaches again the beginning probably the Symbol index doesn't remain to 0. Check the project to have a better idea of what I'm trying to explain!
TIMELINE RESET WORKAROUND
I also found a workaround, I move manually the internal Timeline to 0:
AB.hype.zip (24.0 KB)