Existing labels duplicated on first login post upgrade

With the first post-upgrade access to the release of the 5.8.0 mail module, the already existing profiles are now duplicated labels (see image)

Steps to reproduce:

• before upgrading, access the webtop and check for single labels
• proceed with the upgrade to release 5.9.0 (mail module 5.8.0)
• access webtop again and check for labels

Expected behaviour:

• the labels are single as before the upgrade

Actual behaviour:

• the labels are all duplicated (see image)

When logging in with new users after the upgrade, the labels are single correctly