I have a TASK related to an object
OWD for activity is- Controlled by Parent and the task is related to abc__c object that has
Read, Create, Edit on object level and Private on OWD.
The user's profile has
"edit task" permission as well. However the user is unable to edit the task owned by him where abc__c is also created by the same user.
User is unable to edit the TASK owned by them.Also the related To object is also owned by them.