RAVE Valve

Recently purchased a used 2001 GTX Di with 85 hrs run time. My familys first PWC, it ran really well for the first 4 hrs then the RAVE valve stuck / melted (mechanic said) I am using the correct spec Seadoo oil.
My question is are these valves a problem generally and what maintenance is necessary with them. Also with the injection system is there a injector cleaner additive that can/should be used?

Did the engine have any prior work? Maybe it was bored and they didn't machine the rave valve to match? Maybe someone bumped the compression so that you should have been running premium or even race fuel?
The valves need to be pulled out and cleaned periodically, but sticking will just cause loss of performance, not melting. In any case, for sure whatever oil you put in it didn't do anythihg in 4 hours.