Error When Transferring Ownership of Action Plan

[colin-gyansys]

User has full access to the Action Plan record as the owner but when trying to transfer the Action Plan to a new owner, the actionplanownerapownerchange page throws an "INSUFFICIENT_ACCESS_ON_CROSS_REFERENCE_ENTITY, insufficient access rights on cross-reference id: <the 15-digit ID of the Action Plan record>" It also indicates "Error is in expression {!save} in component apex:commandButton in page labsactionplans:actionplanapownerchange: (LabsActionPlans)"

There is a sharing rule to provide the user Read-Only access as part of a group, so they should still be able to read the record after transferring ownership and should be able to transfer ownership as record owner. I changed that sharing rule to give read/write access and change of ownership didn't work.

Is there anything specific that we need to look for in terms of custom permissions or anything like that that might be preventing the ownership change? It appears that record access should be sufficient for the user that is experiencing the issue.