I heard the same and try to re-position the valve when it is not under pressure. We have had ours since April 2017 and no issues with the valve. Has been repositioned a few times under pressure. I have a spare valve kit in case it does fail. O-rings that are not lubricated do dry out and shrink over time.
Found the part - but they no longer carry it.
http://www.fitzilla.com/Store/page188.html
Found it here:
https://www.abcorv.com/product-page/200rv-rk