AsyncPeriodicWork (and AsyncAperiodicWork) print a message to the log file every time they run. If a task runs every couple seconds, you can get megabytes of text under logs/tasks/ like

Started at Mon Oct 11 20:49:40 UTC 2021
Finished at Mon Oct 11 20:49:40 UTC 2021. 0ms
Started at Mon Oct 11 20:49:42 UTC 2021
Finished at Mon Oct 11 20:49:42 UTC 2021. 0ms

This is not useful information, and besides consuming significant disk space, it produces a lot of I/O activity and degrades performance of backups.