Problem with forced durations of notes


I’m engraving a piece of a contemporary composer. Here is a problem I’m not able to solve. Please have a look:

Its a 7/8 bar. So the challenge is to write double dotted half notes in the last bar. Normally Dorico writes a half note and a tied dotted quarter note. But thats not the result I want to achieve. So my workflow was this: I forced the duration (o) of a double dotted half note. Thats easy. Then I tied (T) one note of each double stop:

Thats fine. But as soon as I tie the second note of a double stop, Dorico ignores the forced note duration:

How can I handle this issue? I have no idea …
Thanks in advance!

Make sure that force duration is turned on at the point at which you add the tie.

For that matter, if you set the following Notation Option then you don’t need Force Duration at all.

It works for me, but only when I re-engaged force duration (o) for the final tie. (In other words, the force duration status is not “sticky”).

OT: Pepinello, there’s a typo in your viola part: the low note of the double stop should be an (open) g, not low e.

@PjotrB: Thanks! I didn’t see this mistake in the original file. Thank you!
@musicmaven and pianoleo: yes. since I have to engrave an existing file I have to re-write these passages.