You can find and upload your SMAPI log by following
the instructions at this site. The reason I mentioned Automate specifically is that if you had a line of chests touching the shipping bin, it would have processed all the stuff in them by selling it. If you don't have that mod, it could be another one, but log is a good first step :)
(Since we don't know yet that it was related to the vanilla game, a forum mod will probably move this thread to mod support unless/until it happens on an unmodded new save!)