

Every instance I’ve seen with actual details has been improper use of real property tax exemptions. In many states you get a discounted tax rate by declaring your home as your primary residence. If you own several properties you only get the discount on one, which is supposed be the one you live at the most (ie primary residence).
The “fraud” part comes in play if you claim multiple properties as your primary. It’s harder to do that if the properties are in the same state, but it’s easy if they’re in different states since states don’t talk with one another. It’s so easy that it’s often accidental.
We’re talking a few grand a year in tax savings. It’s ripping off your state by under paying and people in these positions should know better so it’s harder to give them sympathy, but elevating what may be an accident to a supposed major scandal is a silly headline making exercise.
And why is this happening? Retribution, of course: first person I recall being attacked in the manner recently was MTG.

So signal not compromised, but a member of the chats was leveraged to share its contents.