At the moment I'm using Google Chrome on Windows 10 to fill FMA data on https://www.wikidata.org/wiki/Q27050939. I take the FMA ID data from http://xiphoid.biostr.washington.edu/fma/fmabrowser-hierarchy.html?search=Anterior%20ramus%20of%20spinal%20nerve&entryPoint=none&extendHierarchy=false
I copy paste and get:
Could not save due to an error.
Malformed input: 8733
If I put the number in a box and again copy pasted it I can successfuly put it into the box. I guess there's some invisible formatting copied that prevents the data input from working immediately.