Mist Coat New Plaster - Doesn't Seem To Help

[V8RX7]

I always mist coat new plaster using at least 50% water and applying it so it is a thin patchy coat.

However I've been using the lightweight coving (which is great stuff) and is stuck up with an "adhesive" that is very similar to caulk.

I have then scraped the still damp excess adhesive off the wall and it immediately removes the paint and mist coat and leaves a jagged edge - ie the paint hasn't been absorbed into the plaster and is just sitting on top of it.

I thought the whole point of the mist coat was to stop this happening ?

[V8RX7]

Thanks but surely more water can only help and must be similar to wiping a sponge over first ?

I haven't seen anyone sanding new work before but I'll try it next time.