efflorescence along beads

Hi, I am currently replastering a large ground floor flat and have had some efflorescence come up in the first area i plastered but only along a few of the angle beads and am at a loss to explain it so thought i'd bring it to the experts, i've been using the site for reference for a while but this is my first post.
Ive been plastering for about 6 years, on my own for half of that and this is the first time ive had anything like this called to my attention so im pretty confident its not due to bad practice on my part but as my training and first 3 years work was almost exclusively on new builds, damp issues are something im having to find out about myself as they come up and this has me stumped, so i would apreciate any thoughts/feedback.

Walls were sealed with PVA, and beads fixed with bonding, quite thick in places to level it out as the top half the room had been artexed, but nothing too excessive. it was then given another coat of pva and over skimmed with multi a couple of days later.
The first area it came up was under a new window where the sill had first been patched up with sand & cement but the second area is away from the window and had nothing done to it except the method described in the previous paragraph. there were no visable damp problems in this area of the property prior to my start and it looked like it was treated for rising damp at some point in last ten years or so though the property had been sat empty for over a year before the renevations began.
Sorry thats a bit of an essay, wasnt sure what info would be usefull so put everything!!

It looks like damp.

The window looks like it is getting in under/around the frame, or rising damp (which is what the patch in the corner looks like)

The anlge bead looks a little high perhaps for rising damp if over a metre, is there any way there is ingress there?

Depends on other advice here for a shortcut , but it looks like

1 - find out if damp or ingress

2 hack off and waterproof render ( only use battens to float then a thincoat angle to skim)

penetrating dampness imo! check the cill outside that window.

Thanks for the speedy replys, i had a quick look the other day on a fag break and the window looks pretty neat but i'll have a closer inspection tomorow. Micilin sorry probably should've mentioned the damp patch in the corner (im assuming you mean bottom left of the 3rd pic) is actually a damp patch i'd done earlier in the day after some pipes were moved

I try to keep bonding away from cills and window revels. If there is moisture or damp in the area the bonding will pick it up...You have to be certain there is no damp around when using bonding in those areas...

Aah, thankyou roy, i was not aware of that! is hardwall ok for patching round windows or is waterproof render the only way to go?

Had a look today and there's a chance for penetration round the window but i cant see how its getting to the other area. both areas had a bit of leveling out done as the beads were fitted is it not strange that the only signs seem to be along the bead?

hi SS!

i have to chime in here as i've just skimmed a dining room and i beaded around the french doors using board/thin coat bead, wen t back kin today to finish off and found small traces of efflorescence around the bead area, nowhere else! the beads went straight onto the old painted plasterwork and noticed NO signs of damp anywhere.

Hey trowel monkey, im glad its not just me, strange one! but that said had another look round today and theres signs its starting to come through away from the beads now..