Unreliable pay/terrible benefits- I had more mixups with my pay than any other job I've ever been at. getting my insurance correct was next to impossible. And any mistake on their end, even you failing to get paid, is "just a hiccup, please be patient", but if it's a problem for them, they'll put through a request to the bank to reclaim even an overpayed dollar.
terrible culture - Everyone there is a boring stick in the mud, heads-down coder. They'll go to their supervisors and hr if they don't think you're putting in the right hours.
Onboarding is a nightmare - took a full month before I even had a functional workstation, a month after that before I had any clear idea of what I'd be doing.
the work sucks - Even the senior level developers are stuck coding hundreds of versions of if-then statements. skill wise, the work you will be doing will be that of a college intern, so don't let the pay tempt you... unless you want to stay there forever, you'll gradually become LESS marketable as you work for this company. No one has the faintest idea of any kind of long term plan, and so half your work ends up needing to be redone because requirements were wrong, or assumptions were wrong... etc.