Labels on emails disappeared after settings were made

Hello everyone,

We have “restructured” the labels in our company (added new ones, removed old ones, reassigned colors).

This has worked well for everyone so far. One user deleted all the labels in his program because this was quicker than restructuring all the existing ones, etc. Shortly afterwards, the labels on all emails disappeared for all users except for 3 labels. After a few minutes, other labels appeared again and in one folder no labels were removed; they all remained.

Has anyone here had similar experiences, or does anyone know what happened here?

Best wishes

Addition:
A few labels on emails are visible again, but the majority are no longer visible and no labels are assigned to the read emails.