So the issue is even weirder than I thought. I had the SD card screen up when I turned off the system. I unplugged the power and HDMI cables for 10min, then plugged everything back and turned on the system with Sydney Hunter in the cart slot. On screen was a frozen version of the top half of the SD card menu that I was on when I powered off the system, but the audio made it clear that it was actually playing the cart in the background as the music for Sydney Hunter was playing. Pressing buttons on the controller did absolutely nothing to get me out of the stuck screen. As I had done in the past, I removed then re-inserted the SD card, which unlocked the screen and went straight to the game.
I didn't notice this earlier, as I was testing the system without audio.
Got a few videos to show the issue.
EDIT:
Just wanted to add that I tried to use the contact form on the CollectorVision website to report this issue, but I keep getting the error "Database error occurred. Please try again.".