When trying to update WPMU plugins via either Wordpress Plugin updater, or WPMU updater, it fails. For WPMU: Could not find update source is shown in red at the top of the screen.
Had the problem with a slightly old version of WPMU DEV plugin, and updated it manually. Now it's not on the list of plugins requiring updates, but it didn't fix the issue.
I see others with this problem at various times, but didn't see any solutions.
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