Guy King wrote:
Chris Cowley csaid

Where exactly is one supposed to put PTFE tape if not on the thread of
compression fittings?

Well, I've never used it on compresion fittings - I've always used it on
taper-threaded iron fittings.

Or on BSP female tees with parallel threads, again for iron elbows etc.

Wall plate elbows ...

Spotting a pattern here, where the thread is involved in the seal.

P.