Doesn't appear to affect 0.18.x - just more recent (could be something to do with scales browser).
Its not specific to models, but also affects data files.
It comes from within the Cytoscape graph view - but only appears to affect assets - not ISA elements or Publications
Fixed in version 0.20 - we are not quite sure why but cannot reproduce after adding the asset pipeling
I started to have this error again locally