
Well my bitch did this to me on 4th February spotting for one day the day after her daughter came in season.
She stopped and has now come in on 17th February properly.
I have had it happen a couple of times with mature older bitches that have already had pups, when there has been another bitch in season.
I am hoping to mate her this time as she missed in October, so hope the season progresses as normal now.
The two previous times with two different bitches, both came in season as if they had not had the false start, so it wasn't continuance of the previous, but a fresh start. with both it was about a week or two later.