No extrusion after first toolchange (IDEX 500)

Hello, I have weird extrusion problems on my V-Core 4 IDEX. When printing in single mode, everything is fine. It doesn't matter which tool head I'm using in single mode. If I try to print any dual colour models, both extruders stop extruding during printing moves after the first toolchange (as seen in the picture). I could correct the other issue with the shift. Otherwise the extrusions still work, I could see that during the toolchange movements. I tried slicing with PrusaSlicer and OrcaSlicer, the results are the same. Both slicers were configured according to the documentation. I have not tried mirror and copy mode.