Modules missing after migration from 7.14 to 8.6

Hi all,

on a test instance i upgraded our productive 7.14 version to 8.6. This process went on rather smoth with following the migration guide. As merge mode we took the standard keep mode.

Unfortunatly in this upgraded instance many modules are “somehow” missing. All standard modules that i have extended by couple of fields and all modules created in module builder are not present in all menus.

As i have active dashlets showing some selections of Opportunities, i can still “go to the opportunities”.

See the screen of the dashlet

Opportunity is still there

but also the relationships do not seem to work correctly as seen in the subpanels

Also going the other way around like via Accounts, the link to Opportunities seems not to work

In the Module Loader, Studio … all modules are present. Also in the Module Menu Filter everything is correct and shown, but not visible.

My prod log is flooded with topics like the following

We are using MariaDB 10.6.15 and PHP 8.2.10
The test instance is on the same machine as the productive version, so no changes on that side.

Do you have a hint to point me to the right direction?

Thanks in advance!

BR
Andi