Inevitable Darkness Bonus Item rifts not showing up in pre-existing/New playthroughs

[Dekkion]

So I defeated Inevitable Darkness from the Inevitable Excess DLC on Core difficulty. I loaded saves from previous playthru's and went to the appropriate areas (Act 2/Martyr Zacharius' Cemetery, Act 3/Abyss spot near Playful Darkness). No rift, no item in either area. No biggie, I wanted to start a new playthru anyway so I did so, thinking maybe the import from the DLC was wonky.

I started my new run, and upon entering Martyr Zacharius' Cemetery for the first time, I see my portal and claim my ring. All good, except I realized I missed the Storyteller in the Crusader camp so I reloaded an earlier save since I didn't want to wait to see him in Act 3.

All good again, or so I thought. Now any save I load that preceded entering the cemetery loads a version of that area WITHOUT the portal. I am not amused.

So, are these portals' availability coded for a single instance per character, regardless of reloading different saves, or maybe a cache issue, or just a plain old (and very irritating) bug?

Anyone who has some insight and/or ideas to get around this, I'd greatly appreciate your input