I'm having this problem with a print of mine, its a large mostly flat print shaped kind of like a table with short legs.
because of the shape it has to print supports for the entire structure, now, my leveling is fine, my raft prints and sticks perfectly, and the supports start being build - but after a few layers, it seems like the print head is pulling one of the supports with it and causing the whole thing to tangle up.
There are 4 holes in the structure and i think the supports are being pulled up when it gets to the holes.
I have attached my stl and pictures of the issue.
you see the intact hole at the bottom, i guess no raft or support is built there because my object has a hole in it there, but you you look at the top where its a mess, thats where the second hole would have been. it looks to me like its pulling the supports off when its trying to do that hole? if you lok at the other picture, there are 2 smaller holes close together, one has built ok but it looks like when doing the supports near the other, the issue has occured again.
I am running the print again now with "Support Base Layers" set to 2 to see if creating a solid base for the supports will stop them being dislodged, I have also change the supports "vertical seperation layers" from 1 to 0, again to try and create a stronger base.
beyond these 2 tweaks im out of ideas, any help would be creatly appreciated.
oh some other technical details:
Printer: Creality3D CR-10S Pro V2
Filament: Technology Outlets 1.75mm black PETG
Nozzle Temp: 235 (this gave the best results on S3D's heat tower
Bed Temp: 70