The problem is that they probably are sleeve bearing, like the Gigabyte ones that i had to change on a 1060 G1 Gaming.
I decided to RMA them.
Check the links below for info.

http://cryptomining-blog.com/9268-more-on-gigabyte-windforce-vga-fans-for-gpu-mining-rigs/
http://cryptomining-blog.com/9237-fixing-gigabyte-windforce-vga-fans-for-gpu-mining-rigs/