Yeah, this happened to me (late 2021): was laid off, had at least one Sr. Director in an adjacent silo spinning up the process of lateral'ing me into his org, but HR confirmed that I would have to pro-rata repay severance should I resume FTE during the severance-paid interval (in my case, 6 months). I wasn't surprised as the last thing HR and bean counters want is to let an employee "double-dip", but assuming the interest of the Sr. Dir. in my case was genuine, it's a classic case of myopia on their part: it seems pretty likely that when a layoff is being planned, that there is nothing resembling pro sports' "waiver wire" where a list of all the employees initially chosen for layoff is circulated amongst all of management to see if other orgs want to (offer to) "claim" any of them (they presumably don't do this for secrecy reasons). I took the severance and didn't look back; their decision and process, their loss.