I completely feel your pain with this ridiculous issue. We’ve spent days trying to figure this out without any success. But alas-we have just now figured out what’s going on! (At least with our machines)
To Fix this issue-
Control Click on your Sequence>Sequence Settings>Render Control
Make sure your frame rate is set to 100%
Also, make sure Resolution is set to 100%
Codec: “Same as Sequence Codec”
We checked OFF “Frame Blending For Speed” but I think you can leave it on if you want. Your choice.
Your rendered video should now be regular speed.
Hopefully this fixes the issues you’ve been having!
Good luck!