Cannot use 'in' operator to search for 'message' in upstream request timeout


I have data shuttle set up to delete rows and then add the rows from the new file and it works most of the time fine. Today the below message showed for the first time and instead of first deleing the rows it added in the rows so I ended up with the double the rows!

File was uploaded again and it processed correctly.

I couldn't see anything referencing this error when I checked on community - has anyone seen this before?

Thank you