Steps to reproduce:

1. Add fre-FR language.
2. Fill Description field in Folder Content Type and Description field in its Name fieldtype.
3. Create Folder in fre-FR language, check for description tooltips.

Result:
You will be able to see only the Content Type global tooltip description but you won't see fieldtype tooltips as there is no fallback like it's done for global tooltip.

Expected result:
You should see all tooltips, the behavior should be the same for fieldtypes as for Content Type global description.