I am trying to change my region codes to show region names using custom map, but the values are not getting saved. I am not getting any error, but when I go to data model and open the field properties within the table it still shows codes instead of the custom names set up.
Does the field contain NULL values? What version are you seeing this with?
Maybe this issue is related:
I am also experiencing this bug on version 0.30.1. I can confirm there are no NULL values though I don't think this bug is related as the options for "Use original value" and "Custom mapping" are both available:
The custom mapping just doesn't stick. If I update these values > click save > leave this page, and then return to this page, the original values are present.
Are you getting anything useful in either browser console or in the Metabase server log when doing the save?
What browser are you using?
Super weird: I just checked out my dashboard and the mapped values are showing correctly. The custom mapping is now showing the correct mapped values even though the screenshot I had sent previously showed the unmapped values (I did not change anything since then). Seems like there's just some sort of delay when saving these mappings.
I’m seeing a similar issue to the one described here. I believe the issue is that the custom mappings are lost when the field is scanned and values cached.
Is this desired behavior?
@mtucker I think you might be seeing this issue:
https://github.com/metabase/metabase/issues/9115 - upvote by clicking 
on the first post