KeyError: 'custom' when loading file

[hybridherbst]

When loading the attached file, I get KeyError: 'custom' and the file only loads partially in the graph viewer:

The file: Plane.mtlx.zip

Here's the log (in dev mode):

DEBUG:QuiltiX.qx_nodegraph:updated mx xml data
INFO:QuiltiX.usd_stage:applied material /MaterialX/Materials/USD_Default to /Calibration_Mesh/Calibration_Mesh
INFO:QuiltiX.usd_stage:applied material /MaterialX/Materials/USD_Default to /Preview_Mesh/Preview_Mesh
2025-07-09 23:47:19.055 Python[82185:10639660] The class 'NSOpenPanel' overrides the method identifier.  This method is implemented by class 'NSWindow'
DEBUG:QuiltiX.qx_nodegraph:loaded definitions from /Users/herbst/git/needle-engine-dev/projects/Needle Engine 2021 URP/Assets/MaterialXExport/Plane.mtlx
DEBUG:QuiltiX.qx_node:Initialized Shader_graphs_nprgraph of type Other.Shader_graphs_nprgraph
DEBUG:QuiltiX.qx_nodegraph:created_node <Shader_graphs_nprgraph("Shader_Graphs_NPRGraph_properties") object at 0x30c587c10>
Traceback (most recent call last):
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/quiltix.py", line 545, in load_mx_file_triggered
    self.qx_node_graph.load_graph_from_mx_file(path)
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/qx_nodegraph.py", line 778, in load_graph_from_mx_file
    self.load_graph_from_mx_doc(doc)
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/qx_nodegraph.py", line 808, in load_graph_from_mx_doc
    cur_qx_node = self.create_node_from_mx_node(cur_mx_node)
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/qx_nodegraph.py", line 944, in create_node_from_mx_node
    qx_node.update_from_mx_node(mx_node)
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/qx_node.py", line 127, in update_from_mx_node
    self.change_type(mx_def_type)
  File "/Users/herbst/git/QuiltiX/src/QuiltiX/qx_node.py", line 327, in change_type
    original_values = self.properties()["custom"]
KeyError: 'custom'
qt.pointer.dispatch: skipping QEventPoint(id=1 ts=0 pos=0,0 scn=719.035,685.57 gbl=719.035,685.57 Released ellipse=(1x1 ∡ 0) vel=0,0 press=-719.035,-685.57 last=-719.035,-685.57 Δ 719.035,685.57) : no target window
DEBUG:QuiltiX.qx_nodegraph:node_selected<QxNodeGraph("root") object at 0x134738680>
DEBUG:QuiltiX.qx_nodegraph:node_selected<QxNodeGraph("root") object at 0x134738680>
DEBUG:QuiltiX.qx_nodegraph:node_selected<QxNodeGraph("root") object at 0x134738680>

I went ahead and commented out the parts accessing that:

and then I can at least load the file without error (but it doesn't look correct, I will open another issue about that):