Nightly 2.0
Something about the 2.0 nightly version: It might be the same for other instruments too, but I know that the clarinet is quite messed up. It plays a first higher than it should, and the low B and Bb are automaticly written as high B and Bb.
I hope it helps :)
Comments
Thank you for the report. It's a known issue introduced by development on the transposition feature. See #25275: [2.0] Bb Clarinet Bb and B notes transposed.
It's also a good reminder that Nightly builds are not meant for anything serious.
One last thing, it's better to discuss nighly related issues on the technology preview forum http://musescore.org/en/forum/687