MSSQL Server Backups Event ID 3197

We're running MSSQL Server 2012 on several Windows Server 2012 R2 hosts. We're running a third party tool for backups, which runs every night, but we've noticed the databases on each host seem to get backed up every four hours by some other process which freezes our DBs for a brief time. Is this a normal MSSQL process? There are no errors regarding these processes, but our DBA complains that it slows workloads he's running. Can it be disabled or modified?

In Event Viewer we see:

MSSQLSERVER Event ID 3197:
I/O is frozen on database XXXXXXXX. No user action is required. However, if I/O is not resumed promptly, you could cancel the backup.

MSSQLSERVER Event ID 3198:
I/O was resumed on database XXXXXXXX. No user action is required

MSSQLSERVER Event ID 18264:
Database backed up..... ...This is an informational message only. No user action is required.

MSSQLSERVER Event ID 3014:
BACKUP DATABASE successfully processed 0 pages in 4.637 seconds. (0.000 MB/sec)