I have the same issue as reported a week ago on the FR955.
I can use PacePro successfully for previous (non-course) saved PacePro plans.
Yesterday, I created a course (Lausanne Marathon) in Garmin Connect and then created a PacePro for this course (with each 1km split time edited). Loaded this to the watch. Powered it off an on. Then went for a run to test it today. I viewed all splits on the PacePro strategy, as when I previously had this issue some years ago that resolved the issue. Not today, though. The target time for the first km is shown in the PacePro screen, but the progress bar does not change and so the ahead/behind is never updated (stays at --:--). Eevn after I had run a km, and the auto lap informed me of that as usual, the split progress bar had not changed and still showed no movement. I tried all combinations of selecting Course, PacePro, Navigate Course etc. to no avail. I re-tried the old non-course PacePros and they worked OK. Then re-tried the new course PacePro and still not working.
As the marathon is on Sunday (day after tomorrow) it looks as if I'll be writing my target splits in biro on my hand...