It appears to affect a lot the vibration of the printer and the input shaping seems to be calibrate with this thermal patch correctly mounted.

Here a picture with and without the y motor thermal patch:

I hope this will help somebody. The thermal patch can age and change frequencies affecting the input shaping.

I notice some strange artefacts and kind of blurry faces when printing with blend filament on my Mk4. It's seems that it's not noticeable with more matte filament.

I print the same test part on my Mini to see if this occurs top, and it's not. Both printer use Input Shaper and latest firmware update (5.1.2). Here a picture:

I can't see any vfa on the Mk4 prints, but you'll notice some (If you have good eyes ;)) on the Mini, which is normal.

I don't think it's a motor problem. I check belt tension and it's alright. Maybe a bearing problem ?

If someone has an idea, I take it ! :)

Best