Similar situation... Here is breakdown... I swapped tag lights, and all interior lights (except the dark orange night light from above that lights up the center console) to LEDs. Over the course of the next few years I changed them out to other brands as after about a few months they all began to flicker randomly. After about 8 brands I got tired of buying new ones and just decided to swap them back to original style bland yellow. However, I discovered my tag lights were not working, pulled the bulb out and noticed the bulb bottom was slightly melted. I decided to change the bulb socket and that fixed it, so it appears the socket itself melted along with the LED but it wasn't visibly noticeable except a little on the LED bulb bottom... But changing the socket bulb took about 5 min to change them both. You might have to do the same thing. That's my two cents and probably the fastest method to rule out before digging into the entire wire harness.... My only other concern of note was that I had no parking light issues and it makes sense that the tag lights are just tied into the parking lights, so at that point I would check the fuses, both inside and engine compartment fuse boxes. (It would make sense that perhaps when wiggling and they flickered, that eventually going down the road, the additional wiggling of natural road travel probably caused a short, blowing a fuse. I drive a semi and our trailer lights are the most common to go out due to wear and tear from our pigtail which connects electric from truck to trailer, many times the wear and tear is a slight exposure of the connector end of the pigtail and the natural road travel regularly causes entire shorts blowing the fuse on the truck.)
