Also had to run the following script:
UPDATE tblSystemBigTable SET String03 = 'EPiServer.Personalization.VisitorGroups.Criteria.VisitorGroupMembershipCriterion, EPiServer.Cms.AspNetCore' WHERE String03 = 'EPiServer.Personalization.VisitorGroups.Criteria.VisitorGroupMembershipCriterion, EPiServer.Cms.AspNet'
Any input from Optimizely here? Seems like a bug for me.
VisitorGroupMembershipModel has changed mappings following upgrade from CMS 11 to 12, which breaks already existing visitor groups that uses VisitorGroupMembershipModel.
In CMS 11 it seems VisitorGroupMembershipModel has non-nullable Guid VisitorGroupId, but that changed to a nullable Guid in CMS 12. There is no EPiServerDataStoreAttribute.AutomaticallyRemapStore on VisitorGroupMembershipModel, so in the end I get the following error:
typeBag entry with name 'VisitorGroupId' has a CLR type of System.Nullable`1[[System.Guid, System.Private.CoreLib, Version=220.127.116.11, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]] but the mapping with the same name has a CLR type of System.Guid.
Is it a short term solution to run this query?
Also, following this upgrade from CMS 11 to 12 with many issues I feel you should really start with bug bounties...