Although development diary part 10 discussed correctly tucking beam corners on beamed cross-staff note groups, Dorico nonetheless seems to produce awkward results with partial beams that are not connected to a stem on one side - such as a 16th-8th-16th note pattern:
It would be nice if the secondary “beamlet” would behave as a regular beam in this respect, and get tucked on the appropriate side of the principal beam, so as not to create unsightly hanging beam corners.
Perhaps this bug is farther down the list than some more critical bug fixes and features, but just letting you know that I noticed it still persists in the latest version: 126.96.36.199. In certain rhythmic groups there is still a stray beamlet that is not tucked on the correct side in beamed cross-staff note groups.
To come back to this topic, James has been looking into this one and it turns out that the behaviour is in fact deliberate. It’s based on Gould’s recommendations on pages 316 to 317 in “Behind Bars”. She writes:
When the outer notes of a subdivision have opposite stem direction, place an additional beam so as not to create any unnecessary beam comers. If the sub- division is at the beginning of the main beam, place an additional beam on the opposite side to the first note…
If the subdivided group occurs at the end of main beam, place an additional beam on the side of the first note…
When groups combine both of the above, > it is best to keep all additional beams on the same side of the main beam (it is distracting if the secondary beam moves position - it can look like another additional beam).
So we will think about adding an option for this behaviour.