Intense mushrooms carbonation while fermenting

First attempt on fermenting mushrooms. Pretty low experience level in fermenting overall. So, what I did

1. boiled them for a 1.5-2 hours
2. mix broth and salt so it became 2.5% brine
3. fill jar and put in dark quiet place.

For 2 days there was 0 activity. And then it happens. Carbonation is crazy intense, pretty similar to just opening beer right after initial release. And it keep going like that for over 24 hours already.

I'm not sure if that's okay or not and what should I do with that, if any.

Mushrooms used - regular white champignons.