1, I'd like to ask: Did you boil the liquid before filling it to drive out the dissolved gas in the liquid? Otherwise, with the increase of temperature, gas will escape!

2. What kind of liquid is this? Will it decompose to produce gas due to chemical changes?

I didn't think of it for the time being.

Referring to the first article, if the dissolved gas in the liquid is not removed by cooking, it is easy to produce small bubbles, but the big bubbles are estimated to be due to air leakage in the bag.