I think the concern was if someone had released the fluff for a adventure or class or something under the OGL, then if you went and did a conversion of that for

I think the concern was if someone had released the fluff for a adventure or class or something under the OGL, then if you went and did a conversion of that for 2E and wanted to release it you'd have to do it under the OGL, but presumably you'd also want to use content from the PF 2E rulebook which would require you to use its open license, which would be a problem if that wasn't OGL. It's basically like the problem with GPL-incompatible open source licenses.