Hi,

A bizarre occurrence is happening. I've tried initializing and fixing and nothing seems to work.
It starts to have a random severe flicker, then a complete drop off in exposure, then it steadies out and finally flickers again to end on.

Why if the aperture, ISO, and shutter speed is at a nice gradual incline does the program think it's okay to spaz out?

Screenshots: https://www.dropbox.com/scl/fo/whm79doel...hvddv&dl=0

Most likely it's Lightroom inttroducing contrast flicker due to heave editing with non linear tools.
Please check out my Expert Tips Video #5 to learn about how and when this happens and also how to work around.
https://lrtimelapse.com/tutorial/expert

I removed most all the settings now and went with those green checks. Fixed the flicker but now at each keyframe there's a random spike of exposure, when I manually decrease the exposure for that one frame it also has other contrast issues or something going on? Also not being able to use the shadow tone really is a bummer hah..

New example: https://www.dropbox.com/scl/fi/rcqa3mdd8...0gm3p&dl=0

As I dug in deeper, it looks like its an issue with the Tone Curve, which I thought was a safe bet to manipulate.

It pushes the tone curve all the way to the left just for that one frame. So I've gone back into LR and copied the previous before or after frame to overwrite.

Still doesn't fix the issue of the shadows being severely under...

now at each keyframe there's a random spike of exposure

This is a clear indicator that you either didn't apply the auto transition or that you used edits in Lightroom that are not supported and therefor don't transition.
The parametric tonecurve is supported and can be animated also. The point-curve cannot be animated, if you want to use that you need to apply it on the very first frame, it will then get populated across the sequence, but you cant't change it on later keyframes.
Please try redoing the sequence from scratch - to do so, do Metadata / Initialize in LRTimelapse and remove the sequence from Lightroom. Then start over considering what I told you.