Timeshift uses the good old cron. Manajro uses cornie as a cron implementation. It is installed by default on all official Editions. And it is one of the few services which are enabled by default. If you using a Community Edition or an Architect installation, you might want to check if cronie is running.
If you set up Timeshift correctly, you will have a file in
/etc/cron.d which starts every hour a Timeshift process. This process checks if it needs to create a snapshot. This is depends on your settings in Timeshift.
Check if you can find the Timeshift cron file in
/etc/cron.d and check if it is running.
journalctl -b -u cronie
You should see something like this every hour.
Nov 28 17:00:01 system1 CROND: (root) CMD (timeshift --check --scripted)