Used my original Slash plus today and printed three models in Zabs green. 
All models came out well but a thin film of semi hard resin was on the base of the tray which scraped off okay.
As this does normally  not happen decided pump resin back and clean tray.
When tray was removed oil was between the LCD and FEP sheet causing black tape to peel away.
Cleaned off excess oil and tested LCD which showed Uniz logo as usual
Any advice as to how the oil seeps upwards and what the fault may be, would be appreciated.
A solution would be even better.

Thanks for your help
Tom