It's normal babe, they are figuring out their mouth so will play around xx
Possibly try a change of teat and see if that helps
We’re using the Tommy Tippee closer to nature bottles with anti-colic valve.
we had exactly the same at 12 weeks but with bf - my lo randomly refused to nurse ! but I found it worked for us to just follow his lead and he settled back to our normal routine in about 4/5 days x
Which bottles are you using?