In my case they didn’t. My former boss and I basically met up for lunch, talked about it, and then a few days later I got a new offer letter. I did have to do another round of background checks just to make sure nothing had come up in the months I was gone. They also hadn’t fully backfilled my role (they had hired a couple of contractors during my absence) so it was still technically an available position.

Another thing to note is that when I left previously I did so on very good terms and gave plenty of notice. I’m sure that played a part in how willing they were to have me come back.