The pressure should be regulated by the relief valve (IIRC on the RH side in front of the accessory housing), and secondarily by the cooler bypass valve in case of cooler blockage. Surplus oil from the relief valve is returned to the sump.
I don't hold myself to be an expert, but possible causes may be:
defective relief valve,
defective pressure gauge,
Oil too viscous and cold exceeding the capacity of the relief valve (don't know if this is plausible).
Do you have an oil pressure gauge independent of the engine monitor? That may help to isolate it.
Defective gauges are a common 'cause' of oil pressure problems.
Are you still on a Summer grade of oil?
Does the problem only occur on the first flight from cold?