Error at null with error.message or error.lineNo in workflows

Error at null with error.message or error.lineNo in workflows

All my code was working fine and try catch was fine but I want to match on users uploading too large of files since they're manipulated in deluge so I went to access the error message and am unable to save with an error at null warning. I started by cutting down what I had since it was complex and inside of an iterated subform but eventually I got to the point of copying and pasting zoho's own example into a workflow and the result speaks for itself. However it does save fine as a function. I couldn't find any other discussion of this but it's so bizarre. I guess I could try matching on the exact error line included if that works but that is so fragile and bad.