Is there a dedicated thread to post bug reports?
If so, I couldn’t find one.
Maybe on another site?
Search the forum to see if it’s already been reported. If not, just start a thread here. The Dorico team will see it (there are people from Steinberg on the forum every day) and reply if necessary.
If it’s a known bug, some of the regular forum members might tell you that before the Dorico team get to read it, but two reports of the same bug are better than none!