Plugins not updating properly with WP4.6 on my installation

I keep getting what looks to be an error in WP when updating any plugins.

Update Failed: {“success”:true,”data”:{“update”:”plugin”,”slug”:”all-in-one-wp-security-and-firewall”,”oldVersion”:”Version 4.1.4″,”newVersion”:”Version 4.1.5″,”plugin”:”all-in-one-wp-security-and-firewall\/wp-security.php”,”pluginName”:”All In One WP Security”}}

Got this error when updating All In One. It happens with any plugin since installing WP4.6.
However, the plugin did actually update and when I refreshed the page there is was. I also get an error like this when activating, but it still activates. What gives? lol

Anyone else experience this? I have tried reinstalling WP.

TIA,

Best,
Karl

[ No bumping please. ]