T4 leaky shock issue

[Cliveyp]

Hope someone might be able to help!

Have just rebuilt my dampers on my T4 ready for fridaysclub night and have found one is determined to keep leaking. It's weeping from around the area where the plastic ball cup section joins the orange Alu cap, or from the tiny vent hole in the moulded part. I've tried splitting them down again and fully rebuilding but have got the same issue. It's only one shock and I can't see anything different to the others. It's almost like the oil is bypassing the bladder....

Anyone got any ideas? It was perfectly fine before I took it apart too, which is blooming annoying!