Problems with Parameter Fields

You may be onto something there. If the new field gets added to the Field Parameter table but the change never makes it into the visual.json, that would explain why everything looks fine in Desktop initially but appears broken after a save, commit, or reopen.

What I'd check next is whether Source Control is only picking up the Field Parameter table change and not the visual metadata change. When you add a field to a Field Parameter, Power BI actually updates two things:

1. The Field Parameter table definition in the semantic model.
2. The visual configuration that references the parameter selection.

If the parameter table gets updated but the visual.json doesn't, the visual can end up pointing to an older version of the parameter definition. Manually editing visual.json and seeing it work again is a strong indication that's where the disconnect is happening.

A few things worth testing:

• After adding a new field to the parameter, save the report and immediately inspect the changed files before committing. Check whether visual.json is listed as modified.
• Make sure all report changes are saved before committing. I've seen cases where model changes are written to disk but visual metadata isn't fully serialized until another save.
• Try creating a completely new visual that uses the updated Field Parameter. If the new visual writes the correct metadata while existing visuals don't, the issue may be related to how Power BI updates existing visual definitions.
• Have another developer perform the same change on the same Power BI Desktop version. If they can reproduce it, that points more toward a Desktop/source control issue than a report-specific problem.
• If you're using PBIP format, compare the visual.json before and after adding the parameter field. The missing metadata should become obvious in the diff.

Given that the issue started shortly after the June 2026 Desktop update and you've now identified a visual.json dependency, I'd honestly lean toward a serialization bug rather than anything wrong with the parameter itself. The fact that manually updating visual.json fixes the problem suggests the Field Parameter metadata is being created correctly, but Power BI is not consistently persisting the corresponding visual changes.

If you can reproduce it in a small test PBIP, I'd recommend opening a Microsoft support ticket or reporting it through the Fabric Issues forum, because this definitely doesn't sound like expected behavior.