Just found the answer for this in another post from Spork about Bitwig (I got once my wrists slapped for linking across threads so I won’t…) and I copy it here because it’s related to here:
In VST Transit Join there is a button (record sync) in the transport toolbar, a brown one, next to the the metronome button. This one should be enabled if you want to record. Transit Join is then in sync with the host. That means : if you hit the record button in Bitwig, the record state in Transit will be activated, too.