deskthority

The BTC 53 series reads

BTC 53 series is a series of keyboards from BTC. These keyboards use conductive BTC dome with slider switches, over a PCB.

but

Keyswitches BTC foam and foil

and other remarks.

I've personally come across one (5339 or 5369, linear) and it was definitely foam and foil.

Is the article introduction wrong? Or is it more complicated, somehow?

Definitely something wrong or missing here. I have a 5339 that is foam and foil and the one pictured on the wiki page is also foam and foil. I can't say that I personally have seen a 53 series keyboard that was conductive rubber dome. The 51 series is conductive rubber dome.

I think that was just me being a muppet — the infobox (added in the same edit) has the correct switch type. I've fixed the introduction.