Yeh, need more information on your plug and mould materials. LOADS of combinations that just aren't compatible together.

Easylease and other chemical release agents do have an official shelf life, but that won't be the problem. I've got about 6L of various chemical release agents here in my shop, I think only 2 of them are still within shelf life. The oldest 'expired' in 2009. All of them still work like the day I got them. When they actually expire it is obvious - they go somewhat cloudy.

Having made about 8 medium sized carbon fibre parts now, I am less sure of release agent approach than when I started. I spent a year of part time plug making to build my most recent plug, coated it with 5 coats of easy-lease and on demoulding it destroyed the plug and severely damaged the mould. I have had one successful easy separation from a mould on the smallest of my parts and that was using meguiars wax x 10 coats.
Easy-lease just doesn't ever seem to work for me and when I've asked about problems with it I'm told it's got a shelf life (of what I don't know) and even in a sealed tin it goes off - bad news given the price it is and the lack of confidence that induces when using it!

What combinations/approaches can I use to get the best release when resin infusing using the uni-mould system and epoxy? Can I lay down some P120 sealer on the moul sand then add easy-lease on top or even PVA? If I look at Meguiars gold, PVA, P120 and easy-lease, what combinations give the best part release based on your experiences please? Grateful for any advice as this is a complex mould and I can't afford the time to go back to the start...