Passed through this weekend and can confirm that there are showers available in the non-Schengen lounge (by gate 36). I think the confusion stems from the fact that the area to the right of reception has been boarded up for construction/renovation (this has traditionally been where the showers were located). The showers are now located to the left of reception, just before getting to the "Premium Lounge". The sauna is in the same area.
There was no attendant present, and the agent at the reception just told me to use whatever shower room was available. Luckily there was one 'clean' one available as most of the showers had been used but not cleaned yet...