I too was unable to render the MPD page after the update to 20200501 yesterday. However I can confirm that disabling the DAC in the System page, allowing the PI to reboot and then re-enabling the DAC followed by another reboot DOES allow the MPD page to render for me - all the reboots were automatically started following each of these changes.
I don't have any of the problems reported by Klassicman other than:
Addons menu: Version string stayed at "20200418"
Wouldn't it have been better, given that a reflash of the SD card is required, to bump this version to RuneAudio+Re4 ?
I haven't, as yet, tried any of the new featurers of the release though.
Regards.
Chris