Do a burn test on the dipstick....if you get a crackling sound, it is water or anti-freeze in the oil. If you get black tracers or faster burning, it is fuel in the oil. A slow, even flame means you have only oil in the crankcase. You obviously have increased "oil" level.
My issue with gaining fluid on the 4450 MFWD was a bad injector pump, losing fuel into the crankcase, in as little as 3-4 hours, it was way over full. Sample sent to JD was "do not run this tractor"! Rebuilt the pump over a decade ago and it"s been fine since. Rated 145 hp, pump set at 190, no problems, and it has almost 9000 hrs on it.
Issue on the 3020 with Roosa-Master pump, in the 90s, was that notorious ring that deteriorates and plugs the lines, rebuilt and works fine ever since. Yes, there are multiple reasons why you get fuel passing into the crankcase.