If you push an OEM valve train to higher RPMs, the valve springs will start to resonate at a certain frequency, which can then lift the spring off its seat with the valve train no longer following the cam profile.
The valve then abnormally stays open longer than required and is smacked by the upward rising piston crown.
This can lead to a damaged/broken piston crown, and bent/destroyed valve(s).
Depending on the severity, it can be bent valves and slightly damaged piston, to total catastrophic engine failure.
Eliminating valve spring harmonics and breakage was the reason why the desmodromic valve train was used by Mercedes race cars in the 50's (Ducati did not invent the desmo valve train).
In modern times, pneumatic valve springs were developed for use in F1 and later during the modern MotoGP 4-stroke bikes.
The steel springs are replaced with pressurized nitrogen to act as valve springs.
Not only was the valve train able to work up to 20,000 RPM, but the cylinder head temp was cooler, as a substantial part of heat build up in the head was from the steel valve springs twisting and relaxing during operation.