fizzy kimchi

For the first time i put raw oysters in my kimchi and the cabbage went fizzy… It really surprised me when I tasted it 4 days after making it (2 days at room temperature + 2 days in the fridge).
This batch of kimchi is now 1 month old, there is no mold or nothing like that, it smells good (well actually it “stinks” but isn’t it what we want ?? :), and it’s still fizzy (not the brine, the cabbage).
I could read some topics in the forum saying that a fizzy kimchi is a kimchi that turned bad…
But I eat it raw or in a stew and i don’t get sick and I find it delicious…
I’m 99% sure that it’s still good because I do not get sick after eating some but does any of you ever experienced this fizzy effect in his kimchi or am I so healthy that I can eat spoiled food ? :))