On Windows and Linux, with SDK versions 2.6.1 and 2.6.2, calling the Lua function playdate.sound.sequence:allNotesOff()
causes the simulator to pause and print the following error, twice:
SynthInstrument_allNotesOff: non-NULL value required for argument 'inst'
which I assume comes from the C instrument layer. It's then possible to unpause the simulator and continue (unclear if this causes other issues).
Reproducing this is as trivial as:
local seq = playdate.sound.sequence.new("test.mid")
seq:allNotesOff()
This isn't observed on device, I'm guessing since warnings are disabled and not being a full-on crash this gets bypassed.