The website that I’m experiencing this problem with is very comprehensive, 35 MB in size and consists of very few styled text but also contains a lot of Pluskit photo galleries, some videofilms and five offsite pages. This afternoon I changed some text to check if this would create a folder as I described in my first post and it indeed created a folder “wportal-def.rw6.sb-451708d2-TC1FeA”.