Hello Boris,
Unfortunately, there is no possibility to get the name of a group an object is a member of using the %memberOf% value reference. The memberOf property is of DN syntax, moreover, it is multi-valued. Value references for multi-valued properties resolve into a single random value of the property.
If you need to get the names of groups a user is a member of, a PowerShell script should be used. For us to assist you, please, describe the desired behavior in all the possible details with live examples and screenshots.