Grinding the 5th

The car shifts like butter with the new fluid change. However I am noticing that when entering 5th gear at any RPM, I am getting cringing grind.

Delaying shifts do not seem to help a lot. This is quite worrying as the car is almost undrive-able with 5th gear acting like this right after the fluid change.

Will be switching to Red-Line MT90 and report back.