It may not be as it seems. I just two weeks ago had to change out our original Dometic 310 toilet due to an issue that started exactly the same way!
Beginning about 4 years after we bought our 2012 I would occasionally see the same thing, apparently clean water on the bathroom floor after towing. This problem did, however, slowly get worse over the next few years.
About a year ago I had our rig in with Vinnie for work and asked him to redo the PEX where I had installed a bidet thinking I had screwed something up. Not the case. He said my PEX work was spot on. So where is the water coming from?
During our camping trip over the Memorial Day weekend, we had a bad odor problem in the bathroom. It started on Friday as a mild odor and ended the weekend as a complete stench!
I assumed the seal at the base of the toilet had failed letting odor from the black tank into the trailer. Oh, was I wrong! I became “YouTube certified” on the odor issues with Dometic 300 series toilets. Check it out, you will NOT be happy.
What is probably happening is that the two “O” rings sealing the top ceramic portion of your toilet from the plastic base have failed allowing the water in the bowl to seep around the seal during transit (from movement). If you continue to wait, the seal gets worse and waste water will leak during flushes from the failed seal and pool in the wells inside the toilet.
You will want to change that toilet NOW!!! Do not wait until the odor arrives! I was very lucky and was able to change out the toilet without a nasty disaster inside the trailer. You may also want to spend some time on YouTube seeing how lucky you are to find the issue at the beginning.