new oil pressure sensor, and got oil pressure light

On for a split second and off. For a few times in 10 miles. Oil level's good.

background 1. I have an incident before this, when I was removing the oil filter for access, the filter's o-ring dropped without my knowledge, so the oil splashed everywhere when I start the engine, for like 5 seconds.
then I got everything back to normal.

background 2. i used to mess with the instrument. Now the instrument's needle isn't accurate, oil pressure needle is set on 1/8 of the range without moving.

am I getting a defective oil pressure sender? or forgot, this is a 360.

 

oil temp at 89 celcius ( completely warmed up) and the oil pressure at idle on leonardo fluctuate between 0.6 bar to 1.2 bar.
is that normal?