TL;DR explanation. Chorus is magically replacing stomp slots, even though the stomp slots still say compressor or delay.
I am running OS Version Release 8.0.6.24597 in performance mode. I have been running this version since February 2021. Performance 3 slot 1 is MBritt 65 Voice ACE30 N 3, which is a clean AC30.
In the Stomps section, slot 1 is off, slot 2 is a compressor, slot 3 is off, and slot 4 is a slapback delay.
In the Effect section, slot 1 is graphic eq. Slot 2 and 3 are off. Slot 4 is reverb.
The only locked setting is effects slot 1, which is the graphic eq.
Last weekend, at a gig, I switched to this performance, and suddenly there was chorus on it. It went from being my country/rock edge of breakup clean to sounding like what I'd use for 80s rock clean. I was certain our singer messed with something on the board, so I checked it out and it was fine.
Yesterday, at practice, the same thing happened. Chorus magically appeared on the same setting. Having more time to troubleshoot, I started disabling effects. When I disabled the compressor, the chorus sound went away. If I re-enabled it, the chorus came back. I held the button for slot 2, and verified it still said Compressor. I copied the compressor effect from a different performance, overwrote the broken compressor in performance 3, and saved the profile. Everything was fine.
About an hour later, I noticed the chorus was back. I disabled the compressor stomp and the chorus was still there. I disabled the delay stomp, and the chorus was gone. I held the button for stomp 4 and verified that delay was still there.
I just booted up the amp and took a backup, so I could reproduce the issue and create a support ticket, but so far I haven't been able to recreate it, yet, today. Anyone seen strange behavior like this before?