[Breach]

Hey guys. Really strange issue. Replacedbelt tensioner and belt with OEM parts. Bolts torqued to spec (38 Nm), belt properly routed, and all seems to work fine except that... On one of the pulleys the belt wanders too much to the inside, there may even be 1 mm overhang. Redid the job, same issue. Strange thing is that with the old tensioner and belt it seems to be pretty much centred. Does this seem normal, any thoughts? See photos.

[Conserve]

Without your VIN number it is difficult to see what RealOEM is showing for your car and options available. I say that Because like my car you have 2 options for each components.
(see picture 1).
Other possibility if Mechanical belt tensioner is not seated properly (see pic 2 with the notch circled).

[Breach]

Thanks, in my case there is only one option for a tensioner, and that's identical to what was in the car prior.

I really don't see how it could be installed improperly as there is just a whole in the crankcase and two bolts to tighten but I'll check again.

[Conserve]

Okay. Measure height/ thickness of the new pulley vs. the old one with a ruler or caliper tool to see if the new one is taller.