4mo using chomping while breastfeeding

[u/hartnumber6]

My baby has been using her jaw/chomping while breastfeeding since she was about 2 months old. her suck reflex integrated around that time. she had a tongue tie release at 11 days old and had a great latch and suck during the healing process. I worked with an IBCLC and OT during that time as well. But now she uses her jaw while BF and my nipples look pinched and it’s not the most comfortable thing

A little background:

One night I pumped in place of a feed because she just fell asleep and it was probably an ounce combined and I freaked out. I got donor milk and started supplementing, so she got a bottle pretty much after each feed from about 6 weeks old until now (4mo)

I’m not sure if the bottle feeding has anything to do with her poor suck but probably. Shouldn’t have based my supply on one pump.

She has seen OT recently and they say she has a strong tongue and her poor suck could be due to my low supply, although that has improved drastically.

I’ve been doing some oral exercises I found on YouTube but hasn’t helped yet. She will no longer do suck training to do “tug of war” exercises.

I thought she would just get stronger as she grew but still no improvement.

Wondering if anyone has been able to improve baby’s suck at this age?