Double check your process to try and find possible sources of contaminants, particularly oil based ones.

Are you using new mixing containers, or reusing old ones that you cleaned out iwth a solvent?

Even if the mixing containers are new, try washing with hot sudsy water, and drying them, before using them for mixing. there might be some oil residue on them from when they were molded at the manufacturer.

Assuming the problem developed between the first and the second coat: Did you use a squeegee for the first coats and a roller for the second coats? Or did you use some other tools on the second and third coats which were not used on the first?

Is it possible you got fisheyes n the first coat, too, but did not notice them due to the texture of the weave? If so your problem may go back further.

Could there be any suspended oil in the air? auto exhaust, oil burning heater, etc?

Just a few thoughts.

PGJ