This workaround reminds me of something else that’s been happening with expression maps for way longer than this new bug.
Randomly a track will decide its default articulation is not the first one, but something else instead. Doesn’t matter if the notes have the first articulation as an attribute or nothing at all (I use only attributes).
E.g. I always have legato/sustain as the default articulation for strings, but suddenly they’re playing staccato notes, and it doesn’t matter if I specifically select sustain attributes for the notes. It will continue to play the wrong articulation.
How do I fix this? Put a random note using any other attribute at the beginning, just too high for it to play. That resets the expression mapping and the following notes play correctly again. I’ll have to try if this muted note trick also resets it.
Unfortunately I don’t have a 100% sure reproduction for that, so I’ve never written up an issue post about it. But these bugs seem fairly similar, so I’m hoping the expression code gets a bit of a refactoring at some point…