If the CPU boosts it will spike temp.
Ryzen CPU's boost eagerly even with very light loads (like mouse movement) in order to get it done quickly and put the core back into deep sleep for power saving.
Perfectly normal.
Sorry, but I disagree. Such task (mouse movement) have almost zero impact on CPU workload. On my PC (also 5900X), all cores remain totally flat, no matter what I do with mouse.Perfectly normal.
So that would be perfectly normal thing to expect when a"special" mouse driver makes the CPU boost during movement.....
I assume OP is using some "special" driver (or app) for his mouse.