How long have you been plastering raythePLASTERER ? never heard such b0ll0x in all my time spreading , its got same key as multi i.e. millions of pores in the plasterboard , as for not applying board adhesive directly to boards ffs British gypsum have been doing it wrong for the last 25 yearsjust because something is sticky doesn't mean it will stick to anything, bonding needs a key.