The reason it wasn't caught is a) that I added it in after I was done figuring out the bulk of what was wrong with IGV and b) that the IGV will get the file even if it is not listed as indexURL as long as it lives in the same place as the other one (which in general, the files in Refinery do not).
The reason it wasn't caught is a) that I added it in after I was done figuring out the bulk of what was wrong with IGV and b) that the IGV will get the file even if it is not listed as indexURL as long as it lives in the same place as the other one (which in general, the files in Refinery do not).