Almost a mess!

[Northern Wis.]

We're getting our trailer ready for a long weekend outing and I had a water line connected to the trailer flushing the water lines out because the trailer has been idle for a couple of weeks. I happen to look in the toilet and it had filled with water almost to the point of starting to overflow!
My question, I had flushed the toilet a couple of times to rid the line of possible air. Could it be that because the trailer has been sitting the water valve on the toilet is sticky, and if flushed a few times things will be good, OR is this a sign the water valve on the toilet is failing??
The warranty is up in a couple of weeks-so.
Thanks
Bill

[Old skipper]

I would lean in the direction of pending failure if you have flushed several times without the valve shutting off. Totally different if after use it cleared up.