A consistent defect at 10cm height (and 16cm height) at all prints  

The belt tension

I printed the tension-meter as suggested by @diem, and both belts are bellow minimum. I guess I have to tighten the belts and test again 🙂

Problem solved

I tensioned the belts

Reprinted the cylinder, it was perfect

Reprinted one of the parts, it was perfect

Problem solved, thanks again!

@christian-4

Thank goodness, or Diem in this case.

that was one of the easiest things it could have been.

Enjoy

Swiss_Cheese

Problem solved,

Not so fast: problem mitigated.

The loose belts were permitting some other problem to manifest in the print, you have not fixed that issue, you've masked it.

I suggest it's time for a general maintenance tune up.

See: https://help.prusa3d.com/en/article/i3-printers-regular-maintenance_2072

Cheerio.

Problem mitigated

thanks @Diem, a suggestion could be that the printer had an option for showing a maintenance warning after evert x hours, just an idea.

This is just a user forum, for suggestions to reach Prusa devs go to Prusa's github.

Cheerio,