^ This
(Race Condition for anyone who’s interested in nerdy code stuff and doesn’t know what it is)
We do actually play with sound on & off, but different hardware configurations, cause different latencies on different events/actions in the game, and all of a sudden you’ve got yourself into an untested state.
I’ve seen some terrible things over the years where engineers try to fix problems by adding in delays, and (time permitting) I usually slap them in the ear and tell them not to do it. 
This one got away from us though.