I have a 2008 g35X sedan that I purchased in December of 2017 with about 75K on it.

In July of 2018, the starter went out. I replaced it with an aftermarket re-manufactured one from advanced auto.

2 months later, September 2018, it died again. I came here to the forum and it was suggested that I DO NOT put another part from Advanced on their and go with OEM....I could not find one available so I got one off a wrecked car...

It lasted until August of 2020, when I replaced it with a starter ordered from the Infiniti dealership.

That one lasted until today.

Is there an issue with these starters or do you think there is something else wrong with my car that is causing this?

 

I suspect your positive battery cable wire is damage, possibly also the negative cable to chassis, or the one on the timing chain cover that connects to the chassis below the coolant reservoir.

Something likely is damaged and has a slight bit of electrical resistance, resistance means higher amperage draw on the starter motor, higher amperage draw means significantly more heat generated, heat burns out the windings.

Since you've smoked numerous starters it's probably one of those cables. You can try just unbolting then and wire brush to clean, then apply a very thin layer of electrical anti-oxidation grease. Also feel around on the wires for any bulged or soft spots where it might have a pinhole and the copper conductor is rotting out.