Model Refresh not finding Column Headers and breaking

I have a couple models that have been working fine up until th November update. The models have been pulling data from tables whose structures (column headers) have not changed since the origial development (only the data is being updated). What's happening now, though, is if I run a refresh the process will break because it states it can't find a specific column header title. The problem is, though, that when I go back into Power Query and see what's going on with the tables, the column headers that PowerBI states are not there, are actually there. I don't understand what is going on here and my only thought is that something changed at the Novemver update that has caused the issue because the models will refresh if I use the September release of PowerBI. Can anyone help me on this? 

M codeColumn Header that the Error Notice is pointing toError Notice