New
#11
You could try resetting WU.
Reset Windows Update in Windows 10 - Windows 10 Windows Update Activation Tutorials
Thanks! I think I'll wait and see first if it will get fixed on the 11th first before trying this out (not really fond of playing with the system).
EDIT: Just found out I'm not the only one with this bug:
[OFFICIAL] Windows 10 Redstone 2 - Creators Update - Page 17 - Guru3D.com Forums
[DISCUSSION] Windows 10 (1703 RS2) Final 15063 (PC) - Page 275
March Windows 10 Cumulative Updates are out! KB4012606 (RTM), KB4013198 (1511), KB4013429 (1607) : Windows10
Someone from the Windows Defender team replied to the user with the problem in the last link saying that it's a known issue and will be fixed.