"Contact: No Update" doesn't work for Update Existing Users

Issue Summary

This appears to be another wrinkle when updating an existing user, similar to
#492484: Password being reset on re-import and
#472576: User import for existing users to conserve old roles does not work.

I'm simply trying to add an additional role to an existing user. Under Options, I leave Contact unchecked. And under Update Existing Users, I select the default for Contact: of No Update. Once the update has been performed, I find that for each updated user the checkbox for Personal contact form under their account Contact settings has been cleared when it should have been left however it was previously set.