Bubbles in lining paper after papering and painting

The bubbles should have pulled back by now, I keep a syringe in my papering kit to pull the air out, or use a sharp Stanley blade to slice open the bubble and smooth out, then qently sand when dry, then touch up

sounds like the ceiling was not properly sized , the ceiling needed coated with glue size then when nearly dry apply paper, then give at least one day to dry before painting, allowing time between each coat.

I like the syringe idea 💡. Problem with cutting bubbles with a blade is that you can see the slit afterwards .. ideally bubbles should be smoothed out when the paper is pliable either with a foam or damp cloth or papering brush

The bubbles should have gone back as soon as the lining paper is dry, if not it could also be because the preparation wasn’t good for example if there was wall paper there Before or old lining paper That wasn’t probably removed or not removed at all! That would cause that problem. Walls should be sanded down and filled with a filler We’re needed and then Wall should be cleaned before lining. Another example could be because The lining paper not pasted Probably so missed in areas or because the lining paper is not put up evenly( over pulling not enough paste)