If you have changed them, then you know it is those cussed TL & TG bezels...especially if you have had the housings out of the bed. You have to adjust the housings so the lens will center and clear the alum bezels when you push all those clips into their holes at the same time.
...and if you are off and have to remove a bezel, it is trashed.
I started with repros and then switched to NOS to see if they were any better. NOT...I actually had to work the rough edges on the NOS with a belt sander, to get them to fit...and the edges were rolled over so far that the clips would not slide under.
After I finally got them on I took the rest of the day off!!! Next time I am welding up the holes!