Wirquin waterless trap troubles

[Matt.wr]

Having problems with a wirquin waterless trap that was installed a few months ago. Can't seem to stop smells coming up through the thing. Tried putting some lube on it to stop it creasing, different angles, but it never seems to seal well. Replace the sleeve etc anything I'm doing wrong?!
Link to trap design below.
Thanks!

https://www.google.com/url?sa=t&sou...Vaw2uVQMjQof9UxXoCzhCX54j&cshid=1580993886332

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[WC1]

Replace with maclapine or Osma. Wirquin not well regarded