Maybe I have seen a similar issue
(but on SU4 beta, don't know if that plays probably a role)
I was on a course which had sth like a wide rectangle path.
[image: 87f4610b-0448-436f-81e3-df107cac48df.png]
Original active leg was from the left position to 1
(note: its just for illustration. "1" was not the first WPT on the plan)
Then I set a direct-to to 3.
What happened then was, that the leg from 2 to 3 got magenta.
And the Starship was flying a course like the direction from 2 to 3. But not heading to the leg or to 3. What I would have been expecting was, that it steers at this point directly to 3, maybe "illustrated by a magenta line from PPOS to 3?! But no line was drawn, just the active magenta leg from 2 to 3.
I then made a direct to to 4, leg 3 to 4 got active and Starship was flying to that leg.
Mysterious ...