Is there a gasket on the fastferment lid? If not, there should be for a good air tight seal. If there is one, there could be an air leak there too.
Do you have a string (fishing line, dental floss, etc) holding a bag? If so, that might be breaking the seal of the gasket.
It could be that you have a partial seal, and it was active enough to push through the airlock. Now that fermentation has subsided, it might be bleeding out and bypassing the airlock.
Do you have a string (fishing line, dental floss, etc) holding a bag? If so, that might be breaking the seal of the gasket.
It could be that you have a partial seal, and it was active enough to push through the airlock. Now that fermentation has subsided, it might be bleeding out and bypassing the airlock.