Everything appears to be working as expected when I test.
One line of inquiry I can see from your graph which may be causing problem (albeit highly unlikely, but worth mentioning for the purposes of troubleshooting) is your data structure. It seems like there is a lot of replication occurring based on the output of the node. One test you could try is to input a single import instance and a flat list of layerNames and lineStyleMap and see if you still get the error.
If that resolves it, then you’ll need to refine your data structure - it looks like you are working with rank 3-4 lists. As a general rule of thumb 1-2D lists (rank 1-2) should be sufficient for most graphs, and 3D should be sufficient for complex data structures. DetailCurvesFromCADLayers for example expects singletons and 1D lists and replicates (thanks to Dynamos VM) for higher ranks but if you dont need to replicate, then stick with simple data structures.
If you still have issues, post your graph and a sample Revit file which can reproduce the problem and I’ll continue investigating.