Dictionary has to download again every time I log out or restart [duplicate]

I'm repeatedly being asked to download the "Apple Dictionary" when I open the dictionary application.

Dictionary application needs to download dictionary "Apple Dictionary" before use.

This doesn't happen every time I open it. I haven't pinned down specific usage cases where this message appears, but I think it may be every time after I reboot my computer.

Is there anyway for the Dictionary application to remember that I have "Apple Dictionary" permanently? This has only started happening after I upgraded from OS X Mountain Lion to macOS Sierra.

The Apple Support article “How to free up storage space on your Mac” mentions:

Other ways that macOS helps automatically save space

macOS Sierra and later automatically takes these additional steps to save storage space:

• Detects duplicate downloads in Safari, keeping only the most recent version of the download
• Reminds you to delete used app installers
• Removes old fonts, languages, and dictionaries that aren't being used
• Clears caches, logs, and other unnecessary data when storage space is needed

While the article says “dictionaries that aren't being used”, I have the impression even recently used dictionaries get deleted if free drive space gets low.

I find this “feature” terribly annoying, as I’ve already found myself unable to consult Dictionary.app a few times while offline, but I’m not aware of any way to turn it off.