Error adding user to license group

[rattmice]

When adding a user to a license group, I'm getting the following error when clicking Finish in the popup window:

ATTENTION:

class [B cannot be cast to class java.lang.String ([B and java.lang.String are in module java.base of loader 'bootstrap')

Removing the below properties from the file IEConf/adapterservice.json doesn't help:

• local.xxx.binaryMode=objectGUID
• local.xxx.windchill.mapping.user.attributes=objectGUID

[VladimirN]

Article - "Getting error: "java.lang.ClassCastException: class [B cannot be cast to class java.lang.String" while updating any "User"(adding or removing the group shows the error while finishing the popup) on "Edit" wizard after upgrade in Windchill PDMLink": https://www.ptc.com/en/support/article/CS394080 

[rattmice]

Yes, I referenced the steps in the OP which didn't resolve the problem.