https://bugs.winehq.org/show_bug.cgi?id=49036
--- Comment #2 from mr.lumberg@gmail.com --- (In reply to Olivier F. R. Dierick from comment #1)
Hello,
WineHQ.org doesn't provide support for appimages.
Yet, someone might want to try to reproduce the issue with the standard windows version of the application: http://lmms.io/download#windows
Regards.
Issue is not LMMS itself; VST plugins were working until I ran updates from Debian last night, which pushed out updates to winehq-staging, wine-staging, wine-staging-64, and wine-staging-i386:i386. These 4 packages were the only updates that were pushed out yesterday in Debian Stable that were available for my system.