I´m fairly confident this one had the issue:
Task-ID: 601 - 940a690000174d0871eaad501a48399f
As far as I could tell, all 4 of my builds had the same issue. I know because I was starting to get worried by that point and did a complete wipe, repartition and format of the sdcard before I put my manually compiled firmware on it. After that got my board working I haven't tried the web based firmware again.
The wipe and reformat was most likely overkill, because I've had been using that sdcard on the printer without issues and all the scans I did on multiple pc's didn't show any issue with the sdcard.