Hi, im using Cura 4.0 (tested also same thing on 4.1 with same problem) with Prusa MK3. I found a problem when orienting my model so it is touching the buildplate only with small part (corner) or not touching at all.
In this case it seems like the print settings of skirt and brim are taken from support print settings (thatis my guess what happens) lines are thin and dont adhere to buildplate so it makes to fail whole print. I didnt find any workaround so far (teste support brim, brim only for model etc..).
There is printed skirt on first picture - it is not sticking to buildplate. Model orientation in picture 2.