ORA-01105 ORA-03175

oerr ora 0110501105, 00000, "mount is incompatible with mounts by other instances"// *Cause: An attempt to mount the database discovered that another instance// mounted a database by the same name, but the mount is not// compatible. Additional errors are reported explaining why.// *Action: See accompanying errors.

oerr ora 0317503175, 00000, "parameter %s mismatch"// *Cause: The value of the %s parameter was not the same in all instances.// *Action: Check %s in all instances.

It is found that instance 1 does not use spfile, and instance 2 uses spfile, because there is a spfile.ora under $ORACLE_HOME/dbs of instance 1.

Behavior of Active Dataguard(ADG) When Apply Node Aborts/Crash (Doc ID 1613719.1)
Active Data Guard RAC Standby - Apply Instance Node Failure Impact (Doc ID 1357597.1)

_adg_instance_recovery=true