I borrowed a working NES from my friend and tried my Everdrive N8 on it with firmware 1.23. I Played Super Mario Bros. and got a freeze on world 1-3. It's definitely not my NES that's the issue.
It really looks like there's some obscure bug with the 1.23 firmware that isn't affecting all units. To re-iterate, I did not have this issue with the early OS20 betas (I didn't use the later ones) and I never had any issues on v1.16 or any prior firmware versions.
For those who are not having issues, as well as those who are, when was your Everdrive N8 made? Mine has an assembly date of July 12, 2017 according to the Device Info page. (Firmware v1.23, BIOS version 5, CPLD version 2.)
Update: I changed my SD card from a SDHC (16 GB Sandisk) card to a plain SD card (2GB Transcend), and formatted it FAT32, 32KB cluster size. I played Super Mario Bros again, and got another freeze in World 2-2. It's not My SD card either.
I am using the Blinking Light Win on both NES systems, as I cannot get my Everdrive to boot on either system with the original 72-pin adapter. Is it possible that the issue is specific to OS 1.23 and the blinking light win?
I also noticed, on both NES systems, that I am getting some minor graphical glitching when using the Everdrive that isn't present with a real cartridge. Every so often, a thin line will flicker in the middle of the screen or the HUD at the top of the screen (in Super Mario Bros) will flicker. The game also seems to stutter very slightly when this happens. Occasionally, when Mario enters a castle after hitting a flagpole, half the screen will jumble for a split second before going back to normal.