My 2012 F150 3.7, right at 242k miles. A month ago I went to start it, once started, made a loud grinding noise like the starter was staying engaged. Shut it off, started it again and it has never happened again until last night. Leaving the store, I started it, starter stayed engaged and I stopped and started it a good 5-6 times with the same outcome. Left it there overnight, went grab a friends truck and trailer this morning. Before putting it on the trailer, I changed the starter relay and fuse, it started and I drove it on the trailer with no issues. Once on the trailer I started it and the started stayed engaged. Got it home, off the trailer with no starter issues and hasnt done it since. It is the original starter. Should I dig into this issue further or leave it be?