Re: minwax water based poly for floors not adhering to minwax oil based stain
MinWax polyurethanes SUCK!!!! They are probably the worst thing on the market as far as workable, clear, and smooth finishes go. Their liquid stains are good, but that's about it. Gel stains just don't work at all and forget about using a stain/poly single coat product.
On to your problem. My suspicion is that it's primarily the MinWax poly, second that it's a water based poly going over an oil based stain. Even though they come from the same manufacturer, that does not make the two products compatible. Look for the General brand of poly and use an oil based poly over a water born poly. I can not attest from personal experience, but a few of the regulars that I trust have recommended the General brand of poly and that oil based polys are better for floors because they're more durable.
You will likely have to screen/sand off the first coat of poly before trying to apply another brand/type of poly.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!