Our 38' 1984 Fu Hwa Europa has displayed some of the 1/2" plywood delamination. The ER center floor, under that awful aluminum diamond plate, was one place. Another is the plywood under the berths. Our floors are solid Teak and Holly over plywood. The floors are fine, even up forward where water collects to about 1"+ deep (about 12" below the sole). (The boat seems to trim down by the stern, due to the dink on davits, but there's still water forward. A fix I've planned but not installed is to add a small bilge pump to move the water back to the main bilge sump.)
My vast engineering knowledge (as a retired Architect) suggests that the delamination is really caused by 'rolling sheer'. This is a typical failure in plywood where the stuff is too thin for the span/loading. Since your parquet provides nothing for stiffness or strength, your subfloor has to do all the work. Replace it with thicker, 3/4", plywood. and reinstall your parquet.
Since you probably are unenthused about replacing the whole floor, consider replacing the failed areas with 1/2" plywood doubled between the supports with another 3/4" thick bit of plywood underneath. I think, I say 'I think', you'll get away with this even though the thinner plywood will want to bend/sag over the support joists. Additional support for the plywood in between the joists can be added by adding 'ledgers' to the joists to support it.
I replaced my ER floor with 3/4" PT sheathing grade plywood and added an anti-fatigue mat to crawl around upon. I have not replaced the under-berth plywood; though I sit there, I have not fallen through.