Car makes noise upon ignition, recently fixed CELs the issue?

Hi. I was hoping to get some ideas before going back to a mechanic that fixed my car recently. The problem I'm having is my car makes a noise when I first start it up in the morning. When I turn the ignition, the starter (?) or ignition (?) not sure what to call it makes a short grinding noise first, but my engine runs fine and car seems ok after as well. It doesn't happen any other time during the day if I start my car, it only happens the first time in the morning. It sounds kind of like if you had already started your car, but try to turn the ignition again- that type of grinding noise. I recently had my car fixed, and the noise started right after I fixed my car, so I wanted some ideas to see if any of the previous fixes could have caused this new issue to pop up. Here is some background info:

Recently in order to pass smog, I fixed a couple of CEL codes. I had 3 codes pop up. One was a P0325 knock sensor issue in which the sensor was replaced. The next was a P0420 catalytic efficiency which was NOT fixed, then I had a P1456 (i think....) which was a EVAP leak in which the mechanic checked for leaks in the system, found none, then changed the gas cap. Since the P0420 code was the most expensive, it was left for after the other 2 codes were fixed. CEL was reset, I drove around, but the CEL came back on. The mechanic said P0420 is showing again.

I was poking around the internet and found that the knock sensor is related to engine ignition and thought it might be related to the issue I'm having. My question is- is it possible the knock sensor has anything to do with the ignition noise I'm having?

I was hoping to get some opinions about this before talking to the mechanic. Thanks in advance for any help.

Car makes noise upon ignition, recently fixed CELs the issue?