What caused the spark plug tips to burn out too fast?

This could be a couple things but it depends on what the plugs look like. Can you get a couple pictures of the old ones so we can see what the engine is telling us?

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

More then likely it is running rich which is fouling the plugs but let's start with finding out what they look like and that will tell us where to start.

Below is a guide that will help decipher the plugs which is what we are looking to figure out.

Thanks.

it's not running too rich. the plugs were running clean, normal with the center electros burned completely off in a short time. No misfire or any other DTCs.

If the plugs look normal except the electrodes burned off then that is due to pre-ignition or detonation. Do you hear a pinging or marbles in a tin can when accelerating lightly?

If you have no codes then we may have an issue with the knock sensor. This is supposed to advance or retard the timing if it is knocking or detonating.

Also, you can run a couple cans of injector cleaner through the fuel and increase the octane for a couple tanks just to rule out a fuel issue.

https://www.2carpros.com/articles/how-a-knock-sensor-works

Are they all this way or just one cylinder each time?

all 4 cylinders in a short time. iridium AC Delco spark plugs.

Okay. then you must have some serious detonation. Have you noticed any engine noise? Give the fuel treatments that I mention a try and see if that clears it up otherwise we are going to have to look into carbon build up or leaking injectors.