Sorry, I do not share personal saves. However, I can attach various screenshots. (They're in the spoiler below)
As you can see, the Pokémon and raid tier of the den as shown in the game, matches what was predicted by the PKHeX plugin.
You can also see that the seed and den ID provided by the PKHeX plugin is the same seed and den ID provided by Capture Sight.
So, as it can be seen that all 3 of the factors above agree in terms of information, I have reason to suspect that the error lies elsewhere.
Full disclosure, I've only done 2 RNGs for myself, and one of them didn't utilize Capture Sight, but at the very least the PKHeX plugin has not failed to provide me with the correct frame. Also, I have used Capture Sight to help others calculate their frame, and they indeed got it right, so I have no to doubt Capture Sight.
Perhaps if you can provide screenshots in the same manner as I have, we can identify the problem.