I called Canon. They said that they have had other people call about this interval timer problem. They have no solution as yet. They took my email and will contact me when they know more. They said to register the camera to get automatic notification of any updates, etc. But of course their website is down so I can't register it.
I've emailed support about hot pixels at long shutter and high ISO that cannot be removed with manual sensor cleaning remap as per previous cameras (so far they show on screen and EVF but NR seems to remove from photos automatically). Anyone else have stuck pixels (red, blue, green) or hot pixels when they crank the ISO and open the aperture, or use slow shutter speeds (or all three)? These are on the sensor and appear on both EVF and screen on my R5
I did mention the lack of blackout on EVF and screen as an annoyance for timelapse shooters and waste of power for everyone but forgot to mention this too.
Either way, it seems their site is up and they were very fast to respond and seemed to indicate a repair option may be available if I was not satisfied with high ISO NR (obviously us timelapse shooters cannot use long exposure NR).
Perhaps a few more can email about these concerns? Would love to get a screen+EVF off blackout mode for interval shooting to save power and avoid lights in the dark. Also wonder if they may suggest you send your unit in to more quickly replicate the interval timer issue (I'd hope they would exchange it so you are not without).