needs new seals in he air chambers i reckon.

let all the air out and start again.
let-ve out first,turn forks upside down so you don,t loose oil
put +ve in first.
when putting -ve in fill the right way up until you see the fork just start to pull into the travel.
turn back upside down to take pump off.
have you had the uturn knob off??

Sounds like you have air leaking from the +ve to -ve. Or just leaking out of +ve.

However, you say that the pressures are still ok.

As Rob suggested, you should start over again and always adjust the -ve with the bike upside down, otherwise you will lose oil and any oil in the pump head/pipe might affect the pressure reading, as the -ve chamber is very small.

I would also definitely give TFT a ring. They are usually more than happy to give advise over the phone without giving you the hard sell to send your forks in.