There are not many reasons why this will occur on pre-finished (factory finished) wood flooring. If it does, the odds are very good that it is a product integrity problem. It is also possible that the environmental conditions caused the issue. Unless this problem is shown to have another origin then this problem is most likely a manufacturing defect.
When dirt or debris is embedded in the finish, it means the floor wasn’t cleaned properly before finishing or other contractors were raising dust nearby before the finish dried. Peeling suggests there was a contaminant on the original flooring surface, such as wax, which interferes with any subsequent finish. If all of the wax wasn’t removed, it’s only a matter of time before other areas begin to peel.
Hardwood floors that have evidence of bad adhesion should not be considered for traditional screen and recoat operations. The reason for this is simple. If somewhere below the surface there is an interface between two layers of urethane that are not properly bonded together, adding another coat on top won’t do anything to stop the peeling. It is possible even that the application of a fresh coat will aggravate the poorly adhering layers and make the problem worse. The solution to a peeling urethane coated hardwood floor is to remove all of the coating involved – sanding all the way down to the bare wood.
What causes peeling and how can it be prevented? Peeling may be caused by the application of a coat to a surface that should have been roughened first. The chemical resistance of a cured urethane is so high that it is the increased surface area of a roughened floor that helps the new coat bond properly to the previous coating. Naturally the surface must be cleaned properly also, not dusty or impregnated with cleaning compounds.
The only exception to the rule (that the previous coating should be roughened) is when the previous coat was applied only recently. Fresh coats that haven’t cured completely are capable of being recoated without roughening. If a fresh coat of urethane is allowed to cure 16 hours or more, it should be roughened up prior to the application of the next coat. After 16 hours it will have cured sufficiently to make bonding by another coat challenging. Lightly scrubbing with a maroon pad on an auto scrubber using only plain water is a reasonably fast way to ‘knock down’ the shine from yesterdays final coat before the first coat today.