I'm currently working on an upgrade for a customer, from 10.3.1 to 10.4. While working on that upgrade, we found an issue with pushing serialized content to Sitecore with Sitecore Content Serialization. The error message wasn't terribly helpful, but here is what we received for several fields/items that we were trying to push:

UpdateFieldItemCommand received a set value command, but its value was already equal to the value to set. This indicates sending extraneous commands.

Googling this error didn't seem to return any meaningful results, so we beat our heads against the wall for a few hours trying to sort this one out. Eventually, by looking at the local changes to some of the serialized files, we stumbled across the root cause.

In 10.3.1, these affected fields were not Shared fields.

But in 10.4...

I failed to find this change mentioned in the release notes... ;)

The fields shown above were on the /sitecore/templates/Foundation/JSS Experience Accelerator/Scaffolding/RenderingHost template, but we also found this issue with some workflow-based OOTB templates. I have no idea if these were the only templates affected, but these affected our implementation.

The Fix?

Thankfully, once identified, the fix is simple. Just delete the affected serialized .yml files on disk and perform another dotnet sitecore ser pull.

Hopefully this helps save someone in the future a bunch of time troubleshooting.

Happy Sitecore trails, my friends!