Is v1/metadata/writeback (without immediate) needed?

[ubacher]

I have a script which modifies the metadata in selected files. I find that this causes the yellow pencil to appear on the files.

Do I still have to use v1/metadata/writeback (not immediate?)

[Mario]

When you modify the metadata of a file from a script, the file is marked as pending (so the pen shows in the file window).

The metadata/writeback endpoint is to actually write back the metadata into the file.
From the docs:

This endpoint triggers a write-back for all or selected files. The write-back is performed asynchronously in the background using the normal background write-back processing. NOTE: If background write-back is disabled in IMatch, this endpoint does not cause a immediate write-back, the files are just added to the pending write-back collection. Specify the immediate parameter as true to immediately write-back

So you don't need to use it when you have modified the metadata before. Because in that case the files are already marked as pending and in the collection.