Issues viewing content at 24 fps in Dolby Vision on tvOS 14.6 (and 14.7)

Ever since I updated my AppleTV 4K to tvOS 14.6 update, the match frame rate setting has been unusable for me. I found this out when trying to watch a movie in 4K Dolby Vision and the image seemed very jittery and not smooth. I don't know if it's judder or stutter (or if I could tell the difference). Through some experimentation, I've learned that it's because most movies are shot in 24 fps, and the issue only happens when the video is being output at 24 fps in Dolby Vision (both 24 and 23.98 have the issue). I do not have the issue when outputting in HDR10 or SDR, or at any other frame rate. It's only 24 fps Dolby Vision. I also don't have the issue when I turn off the "Match Frame Rate" setting and just leave it at 60 Hz.

I can also verify that my TV is capable of Dolby Vision in 4K at 24 Hz, as I can play movies in my TV's native apps using these settings without any issues. It seems to be an AppleTV or tvOS problem. Does anyone know what might be causing this issue?

My setup

AppleTV Model: AppleTV 4K (1st Gen)

TV: Vizio M65Q7-H1 (https://www.vizio.com/en/tv/m-series/M65Q7-H1)

Cable: Spigen 8K HDMI Cable (https://www.amazon.com/gp/product/B08PSF95M2/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&psc=1)

Settings

Match Dynamic Range: On

Match Frame Rate: Turned OFF due to issue described above, but would like to keep on if able to resolve

Color Chroma: 4:4:4