Anti-virus software may be preventing Time Machine from writing to the backup.

Antivirus software may interfere with a backup

Though Carbon Copy Cloner is not an Apple Product and Not Time Machine Backup from Apple

There principle remains the same - Get rid of this useless software

Windows-like viruses that self-replicate and affect macOS don’t exist because of the underlying UNIX Foundation and permission limitations.

The macOS operating system resides in a sealed and read-only volume that can’t be opened by users or third-party applications.

This antivirus software only protects the developers’ bank accounts and creates problems for users in return.

Mac app security enhancements are sufficient to protect computers from malware.

Adware and Malware can affect computers and are often downloaded from “shady” websites or developers who inject them into downloads.

Source: User tip from @Kurt Lang

What is malware? - Apple Community

Assuming you have antivirus software installed, uninstall it. It's unnecessary and known to cause problems.