When we try to set the "Priority" field via before update / insert business rules as shown below, it doesn't work.
Any supported release.
Priority look up definition ("https://<instance name>/dl_definition.do?sys_id=302849102b031000de0aba36a3fd5631") is active on all out of the box instance by default and it will override the priority value set by the business rule.
As per business use case, if the priority value needs to be set only by business rule, make sure,
- Business rule is either before insert/update (should not be after insert/update as the current object will not be available).
- Priority look up definition is inactive