After many years of DIY plastering including whole room jobs, I've finally been bitten.
Just tackled about 3 simple square metres. Browning on yesterday easy peasy as usual. Todays finish was a disaster. About 70% just wouldn't stick, blowing off left right and centre. Late 'use by date' plaster was used throughout.
Yes it works best when the browning is still to go off. But it isn't insummountable and I haven't had this problem before.
I thoroughly wet the undercoat[1]. Mixed up enough for half the area and bunged it on.
Did I overwork it too early? Was the wall not wet enough?
[1] These days I bring the garden hose inside and use the mist option. Hand operated sprayers are just too much hard work and RSI inducing.