Alert.log: New timestamp format in Oracle 12.2
Whats new with the timestamp format in Oracle 12c Release 2?
UNIFORM_LOG_TIMESTAMP_FORMAT CANNOT BE SET ON ASM INSTANCE (Doc ID 2308274.1)
It's expected behavior. UNIFORM_LOG_TIMESTAMP_FORMAT parameter can't be set on ASM instance in 12.2.0.1. It will be implemented in future release 18.1.