I think a palomar knot would be a good alternative. It's easier to cinch and tighten down properly than the clinch and improved clinch.

Always pull the tag end first when possible on all knots.

 

Something you are doing is causing friction that damages the line.

 

May I suggest purchasing a different name brand line and tying the same knot to notice if that different brand also is "burned" when you tie the knot?

 

If the knot is successful then the problem is with your line.

 

If the knot fails then the problem is with your technique.

lose the vanish..

After some experimentation I've settled on the Uni for fluoro. No problems and easy to tie.

Thank for the reminder to only pull on the tag end, by the way.

One thing i do before I clinch the line on my improved clinch knot is I straight make out with it, all slobbery with my spit, no friction for sure and knot ties easily, smooth and beautiful! lol its funny but its also true. Get it wet before you finish!