Can my employer take back PTO after it was put in my time bank?

Location: Rhode Island, USA

Our whole company got an email last night saying that our HR person has been ‘closely monitoring balances’ of our PTO banks. Apparently, our system wasn’t calculating it correctly, so they yanked a bunch of hours from a lot of people. Understandably, everyone is super confused and upset. My PTO bank was cut down to almost a third of what it was, and it was not a small number.

In my industry, January and February are our slowest months. Me and many others were counting on the PTO in our banks to make it through the slow season without dipping into savings. It feels like they’ve pulled the rug out from under us, and now I am unprepared and have miss-budgeted severely.

So my question is, they don’t have to honor the PTO that was given? Our sick time was not affected at all. Any advice is greatly appreciated.