@Chris_MN
Can you confirm if it is the SPfile that is created before taking snapshot that is deleted upon completion of the backup, or is the backup process deleting the SPfile used to start the database?
There was a patch in 11.22 (Update 139414) to automatically cleanup the SPfile that was created during the snap backup.
To prevent cleanup of the SPfile, you can configure the below additional setting on the Oracle client.
Name = DELETE_SPFILE_CTRLFILE_COPY
Category = OracleAgent
Type = String
Value = N
https://documentation.commvault.com/11.23/expert/8681_adding_additional_setting_from_commcell_console.html
Let us know if this helps.