Some Electors have a lot of enemies. If you happened to do those ones near the beginning of the run, then denounced a bunch of their enemies, that could have raised their opinion enough to change their mind and go positive again. If you've made other decisions they like as well, that would increase their opinion too (there are a lot of plot decisions that inevitably will affect what the Empire thinks of you).
I suspect that a denouncement which has special attention in the plot may be a true baked-in "will never vote for you" (for example, kicking someone out of a reception in front of everyone after receiving specific incriminating information). However, I'm not sure whether a standard denouncement completely locks out the . I think the most effective way tr troubleshoot this might be to pick up a high-Media person - and then have fun denouncing everyone else, getting Empathy built up as high as possible. It would be an enjoyable run regardless of the result!
A different run indicates that some Electors can change their votes back to you if doing certain options that are still available and if their opinion of you is high enough. However, they are the sort of things that would make sense to enable a vote change even in the context of a denouncement essentially meaning the Elector won't vote for you. My specific example was Vkvy jnf qrabhaprq ohg gura jnf jvyyvat gb ibgr sbe zr svsgrra gheaf yngre jura V nterrq gb trg ratntrq gb Ynhsva. That certainly isn't something that would sneak up on a player and surprise them at the vote.
Please could you tell me how I get the history across to you, so you can see exactly what path I took to get to that state? I've tried saving the log but it doesn't appear to include the history, only the loading details.
I'm willing to send the save file itself, but am aware that copying saves between different people's installations is deprecated in current versions of Ren'Py for security reasons. I'm also willing to compose and send a document that documents what happened on a step-by-step basis (primarily that would be useful if you wanted to see the changes in popularity rating from the Imperial+ surveys I kept doing during the run, since neither the history nor the save file necessarily saves that in a convenient format for bug testing).