Yeah, known (used to happen even with the 5.0 alphas/betas), reproduced, confirmed, etc :/
Not sure if/when it'll be fixed though,
because (as you said) there's currently no devs left who know wasabi... brennan, francis, aus & mig are all gone (and even though wasabi was never their speciality, so are justin & christophe).
Currently, the only workaround is to go into prefs and reset the option. Sorry :/
There's not even any way for me to report bugs at the moment,
because the betalist is dead as well.
My simple solution... stop closing winamp