Finder preferences unset

The preferences in Finder become unset. It seems pretty random. Today the 'Applications' folder was unticked in the Finder Preferences, previously half a dozen folders have been unticked.

I keep all the Finder folder Preferences ticked as my default state, so it's easy to notice when one disappears.

What could be changing them?

What's the best way to stop the behaviour?

I could just take a copy of:

-rw------- 1 user staff 236787 Dec 24 08:08 /Users/user/Library/Preferences/com.apple.finder.plist

and replace it every so often with a cron job, but that seems a very messy solution.

It looks like very big .plist file. Is that the problem? Should I just delete it and then set the preferences again and hope it stops happening?