As far as I can tell, here is what happened.

The guy I did the mold testing for in his locations was behind in franchise payments to the tune of $125k. There was a sale in the works, but it fell apart, and without funding to cover his debt, he filed Chapter 11 and walked away.

Jack-in-the-Box/Del Taco corporate was able to acquire them and are now running them as corporate restaurants, likely while looking for buyers.

Of the approximately 600 locations, about 80% are franchised, the rest are corporate owned.