DSO offered $50k signing bonus but daily rate seems low

Got an offer from a DSO (won't name which one) with a $50k signing bonus, which sounds amazing. But the daily rate is only $600/day, which feels low for my area. The contract is 3 years and the bonus is prorated if I leave early. They're also pushing me to sign quickly. Is the signing bonus a red flag? Should I be worried they're trying to lock me in with a low rate?