This is correct. I interned in the legal department for a large R1 university that was a state institution, and we got so many FOIA-style requests that we absolutely could not keep up.

You might think they're sandbagging you, but you aren't the center of the university. There are likely several pests who send hella requests for stupid stuff, cackling about how they're punishing bureaucrats for being bureaucrats. Plus all the legitimate requests that you don't even know about.

Like what are you requesting that is so voluminous, and why do you think you're so special that no one else is doing the same thing at the same time?