NodeOperationError: Cannot convert object to primitive value at Object.execute

[Igcorreia]

Bug Description

Hi, I never had this problem before. Today, I have updated the version n8n:1.39.1

And suddenly, a working NODE has an error I can’t seem to find a way to resolve:

To Reproduce

I have a complex setup. It's hard to explain how to reproduce it. I have about five nodes spread across the workflow, so I have created a SET NODE to combine them all. I prefer to use multiple, complex nodes.
The SET NODE is giving the error.

Expected behavior

Since the input is valid, it should not give an error. Or if there is an error, it should be more clear where it is, so I can fix it.

Operating System

Ubunto 22

n8n Version

n8n:1.39.1

Node.js Version

Not sure

Database

SQLite (default)

Execution mode

main (default)

[Joffcom]

Hey @Igcorreia,

Can you provide a workflow and the data needed to reproduce this?