It looks to me like frothing, as if the developer is 'fizzing' almost, with small air bubbles on the surface.

The first thing I would do is try another developer and don't risk another film. Then, if the new developer is succesful, take a step back and work out what may have gone wrong with your first option. Perhaps it is agitation that is too vigorous, perhaps check for grains forming around the bottle cap that aren't remixing into the solution, but to be honest it could be a number of things. You could try distilled water for mixing it just to factor out the water quality. And of course if the second developer exhibits the same traits as the first you know it is water quality or your technique.