What is your full 4 digit version?
use error lookup tool ORA-600/ORA-7445/ORA-700 Error Look-up Tool [ID 153788.1] to find listed bugs if there are no listed bugs then raise an SR with oracle support with alert and trace files, also take a look below note. RAC instance using NFS via Netapps report Ora-600 [kccchb_3] [ID 303986.1]
In my case, the second node on RAC usually gets restarted. I understand that there is a heartbeat process, wherein the nodes checks each other's presence.
However, the disconnections are so frequent that I am unable to understand whether the heartbeat is failing due to network connection or any other case. Checking alert log and CRS log doesn't reveal any root cause.