Here's a Nextdoor thread about it.
TLDR seems to be these franchises were sold back to corporate, lost all their staff, and can't find replacements.
Maybe try asking on Nextdoor? Might have more luck there in finding others who have heard it (or getting it to stop). There was a similar situation about a month back where an alarm kept going off at all hours. Turns out a number of folks had heard it, started submitting noise complaints, figured out the offending business, and got it to stop.