Custom block whose last block is a promise misbehaves in compiler

[unybhgfd]

see issue.zip.
issue.zip
the notes plays at once when chose Disable Compiler, but when i use the Compiler, the notes does NOT plays at once

[GarboMuffin]

seems to be because of the "set volume" block at the end of "play note [ ] for [ ] beats". if you make that be not the last block, it will work the same in both, but still a compiler bug