I recently used some of these and used Loctite sealant on the olives
to ensure a seal. Out of 20 fittings 4 leaked and had to be tightened
up until creaking. Two where on plastic Speedfit pipe and the olives
were wrapped in PTFE as per the Speedfit instructions. Previously I
used mainly Conex fittings and never once had a problem. Has anyone
else had problems with these fittings? Are they cheap made in China
rubbish? Anyone have any recommendations of what and not to use? And
who to buy from and not to buy from.

TIA.