I know this is way too late to help the OP but this is for anyone landing here for the same issue. The others had good points ahead of me but as I've recently found there are other scenarios such as a bad head gasket.
The unexpected rise of fluid level could indicate it's been displaced or added to. One way this could happen is that air/combustion byproducts are escaping from a cylinder. This would hint at a head gasket/head leak where combustion leaks to the oil. Most likely the oil would look frothy or burnt, certainly not normal. It may smell burnt too. This one isn't very likely since the pressure shouldn't effect oil level without a few other issues. Just covering the angles.
Another, more likely way a head gasket leak could cause this high oil level would be a coolant leak to oil. If so this would also cause the oil on the dipstick to look milky and should definitely smell like antifreeze.
Lastly, as another responder (P s 2) mentioned, there could be excess fuel getting into the oil, so not a gasket issue but there's a way you can check for that yourself too.
If gas is mixed in you'd likely smell it but you could also try the match test. Gas should make the oil on the dipstick fairly flammable. Normally that oil on the end of the dipstick will not easily catch fire, even if you hold a match to it. If there's much gasoline mixed in it will flare up like a marshmallow in a campfire.
Well, hopefully it's not the head gasket. Good luck.