In the last couple of weeks we have lost the capability to Set Regarding on an Email Activity from its grid view.
It is important to note that we can still set the Regarding field if we open up the detail record on the Activity, set it there and Save and Close. In other words, contrary to the message, there appears to be no problem with the parent record we are choosing. The issues only arise when attempting to set Regarding from the grid. As a workaround, we can open up each record, but this is laborious and defeats the object of having the grid in the first place - to bulk edit.
The log details contains this message: "Creating Entity with an invalid parent. Entity: Email, ReferencingAttribute:regardingobjectid"
Has anyone else experienced this and found a solution?