Grouped hairpins not behaving consistently

dorico 6.10 i can’t get grouped dynamics and hairpins to work consistently. for example:


i have attached a small project to demonstrate the issue:
HAIRPIN_ISSUE.dorico (1.3 MB)

additional info: i found that if i grab the mf in the example above (in write mode) and move it to and fro a bit, the appropriate magic will happen. Putting my programmer’s hat on, this feels like one of several things: a UI “buglet”, a human vs machine disconnect, or, as we like to refer to certain unexplained issues, a UIF (aka “unintended feature”). In any case, i think it may need some further attention.