com.apple.backupd.sandbox.xpc: connection invalid

Are you using the Application >> TMNotifier

https://forums.macrumors.com/threads/time-machine-connection-invalid-error.2388519/

Refer to posting by @ DarkPremium Cho for possible answer only if the TMNotifier application is used on this computer

Short Answer

By virtue of the .xpc at the end of " com.apple.backupd.sandbox.xpc " entry in the log file.

It appears that the Mac app security enhancements built into macOS Ventura is doing its' job.

Longer Answer

To get a more complete answer to " what is that? and how can I stop it polluting my log file? " would required you the user to do this

Log into My Apple ID and create a Service Ticket.

Then, see of the Paid Apple Support Personal will find this issue serious enough to get an Apple Software Engineer to have a look at this issue.

If you are lucky enough, they may

Thank you for your time and good luck

Welcome