Ok, again there are people commenting here who dont know Mazda diesels. I had my last one for 8 years and another CX5 diesel for nearly 3 years before that. Thus, I speak from direct experience.
Do you have the owners handbook?
At the set oil change intervals, the Mazda diesels MUST have their oil data reset in the ecu. This tells the ecu that fresh oil has been added and it changes the way the ecu manages the engine.
So its very important to do the oil data reset every oil change!!! Its just as important as using the correct C1 or C3 oil (depending on what your owners manual says) as I explained in your other post.
There are two ways to do this - dealers can use the Mazda scanner, or, there is a manual way that us drivers can do it ourselves, and its detailed in the owners manual.
It is NOT DONE THROUGH THE INFOTAINMENT SCREEN.
Now I am working from memory here, but…
Turn the car completely off.
Now press and hold the stick in the speedo for resetting trips. While holding it, press the the start button twice ro put the car into accessory mode, and watch to see the master engine warning light blink. That blinking signifies that the reset has been done successfully. You can let go the stalk.
Pretty sure that is it. But check your owners manual.
This is independent of the service reset in the indotainment system, which you should also do.