Very similar projects needing wildly different export times. Did I change a setting unknowingly?

I am editing a video podcast for a client and it is a HUGE project. Eight simultaenous hour-long clips running at once, with multiple backgrounds, lots of audio work, changing frame sizes, etc. There's a ton of assets. I rendered out the first episode and it took about 7-8 hours which is what I expected. The render turned out fine and I was happy with Premiere's performance.

I'm on to the next episode and the format is almost identical, 8 videos, effects, etc. For some reason, every time I go to render this one out, it tells me 49 hours, or 33 hours, or 52 hours. I've let it run for a while to see if the time goes down and it only goes up. This is being rendered from the same computer and there's no extra assets or anything on this project.

I'm confused as to why the render time is 4x what the original is. Is there some export setting I've accidentally changed that shouldn't have been? Or is there something I may have left on the timeline that's eating all the time up? I'm not looking for specific answers, just ideas on what I should check for because I don't even know where to begin to look. What would cause a render to be 4x as labor intensive?

Thanks!