Can 4m sleep regression start late?

My son is going to be 5 months on the 2nd and for the past few nights his sleeping has been horrid. He used to go to sleep during his night bottle and would stay asleep and wake to eat (he had open heart surgery at 10 weeks so his body was waking to eat to catch his weight up) which I didn’t mind and he’s been a decent sleeper otherwise. He even started going 5-6 hour stretches but now he will not fall asleep during his bottle and cries hysterically until I put him in my bed and then after he falls asleep I’ll transfer him to his crib and he’s back to waking up every 3-4 hours to eat. Idk if it’s the regression hitting him a month late or teething or maybe he’s not napping good enough during the day. But does anyone have advice or help or anything? Lol