How many times has this happened?
On a recent trip to France mine did exactly this. A regen for well over 60 miles. Stopped and turned engine off, no fan, no smell, no indication of a regen. Set off and it went into regen symptoms again (high tick over revs, shit running etc). Stopped again, no fan etc etc.
Next day drove fine, did a proper regen that was completed in 12 miles and has been fine ever since, doing a proper regen about every 200-250 miles.
Maybe you’ve just got the same glitch that I had.