A lot of NULL uca1400 entries in information_schema.COLLATIONS after upgrade from 10.5.26 to 11.8.2

I've recently upgraded my MariaDB server from 10.5.26 to 11.8.2. For both I'm using your oficial binary distribution. My server has a lot of databases. I've run and completed mysql_upgrade without any problems. My new MariaDB 11.8.2 works, for most part. It however has a LOT of NULL entries in information_schema.COLLATIONS table. Normaly this is not a problem. However I found that all available mysql connectors in .NET has a problem with this and stops working completly. For test I've created fresh datadir with 11.8.2. Is has no NULL entries in information_schema.COLLATIONS. Why my old, full of databases datadir causes all these NULL entries in information_schema.COLLATIONS ? There were no null entries in 10.5.26 (I've checked) so thats a bug.