I found a way of fixing this, hopefully it fixes it for you guys too.
If you go to where your Premiere Pro Project files are you will see a folder called "Adobe Premiere Pro Video Previews" this will have a sub folder inside with the name of your project. If you go into the correct projects folder and delete all of the files within it and then inside Adobe Premiere Pro application you go to the "Sequence tab" and the click "Render In and Out" this should then repopulate them files without the second set of captions burnt into the video tab.
Hopefully this makes sense and helps whoever needs it.

Same issue despite today being 12/28/2021, running Premiere 22.1.2

The new Beta 22.2 does not resolve this issue of subtitles being duplicated when you edit them,

Sorry for the wait, but a fix for this issue should be in Premiere Pro 22.2 Beta build 029 (posted to Creative Cloud on Dec. 7, 2021). Please let us know your results.

Thank you.

I'm experiencing the same issue as everyone else. The original poster asked for help with this issue on March 15, 2021. It is now December 1, 2021 and there is still no solution? That's a bit pathetic wouldn't you agree Adobe?

So I guess they're just not fixing this? And the fact that I have to restart Premiere for the 608 captions to actually update. And the fact that even when I change alignment of some captions, they simply don't update. Ever. I hadn't upgrade from 2020 because of this issue, but now they're onto 2022, so you can't even go back to 2020, and I just tested 2022. SAME ISSUES. W T ACTUAL F.

Same issue. Glad im not the only one puling my hair out. I thought i was missing something to un check something. Anyway...i had the show captioned, then imported the caption and lined it up. If i were to make any changes to the captions, then premiere starts to display the 608 as well. Strange bug. Its been happening for a while now im surprised ADOBE hasn't fixed this yet.

Having the same problem for several updates now. Very frustrating. It seems to have happened (and I am hypothesizing here...) when I had me interface set up to display captions when the update with the new captioning process came out. I think that took away the simple "turn caprions off" toggle under the wrench.

Still an Issue here. Can´t get rid off the displayed cations in several projects.
When adding cations layer, this is displayed under the unwanted and therefore is not readable.
Only in the program window, not on export, but I have to see, what I do.

Same problem. Very frustrating.

Same issue here. Just updated to the latest version of Premiere Pro. Now i have to uninstall and go back to a previous version just so I can have functioning caption tools. Thanks for the headache, Adobe. Smh.

I have the same issue.

I have an issue with the latest update where all of my captions are appearing as open captions. Uploading 3 screens but I'm told my settings are accurate. Problem is not occurring in Premiere 2020

I started to experience the same displaying 2x bug as soon as I upgraded to 15.1.0

Same here. That's why captions for broadcast editors seems to be easier on 14 (dealing with .srt files).

The 2020 Premiere Closed Captions were better. I mean Closed Captions....not Sub-Titles. There needs to be a great deal of improvement in Captions. 2020 Premiere works better.

PLUS I can "select all" and delete everything on the timeline and the ghost captions remain (Mac 10.15.7, 128 GB Ram, Dual Radeon Pro W5700X)

Nick Condera's screencap is an accurate reflection of my timeline setup.

This bug is still present in 15.2.

We're having the same issue