Hi Christian, this is a problem many of us have encountered in some way. It happens ever once in a while that parts of the print warp and get into the movement path of the printhead, which is not a Snapmaker specific problem, but I had this with my previous printer also. However what is a Snapmaker specific problem is that the print sheet is not held in place good enough by the magnets, and the whole thing including the print is displaced. There are a few solutions for this in the forum - here’s mine: Magnetic print sheet fixation
That said, it will not guarantee that your print will always survive, because with a tighter fixation of the print sheet, it may happen that now the print will break free from the print sheet. However, for me that never happened.