Aye I've kept an eye out for this kind of occurrence -- have yet to observe myself.
For anyone else suspecting technical issues, save & reload is first option to fix issues with this mod. I have yet to pin any down in v43, seems to be stable as i've played it into ren so far, but I intentionally implemented with re-caching on reload as a backstop to the the mod plot tracking functions
Theoretically, if all else fails, and if your save has no other problems, could use ige or fire tuner to re-spawn any stuck improvements (ie just place the same improvement on top of the stuck one), save game, reload, and the mod should be able to find these plots even if the DB got rearranged -- or just delete them from map without replacement, mod should carry on as normal. And even if you delete a valid plot accidentally, the mod should be able to adjust -- none of these stuck plots should ever happen though, could be sign of corruption issues beyond this mod or VP, maybe try full civ 5 file integrity check too
The sensitive moving piece in recent versions is not the plot tracking so much but the build overrides -- pls keep an eye out for any wonky AI behaviors related to builds
edit response:
managed to pull it off again, turns out they actually turn into "steady-state forest" after 10 turns.
did it start happening immediately after a new civ 5 instance and game reload? if so, something up with DB and mod load order i think -- on the other hand if it just starts happening after working correctly for a while from turn to turn, or reload from same session without exiting out from mod menu, its something else.
the "steady-state forest" is a temp improvement that builds instantaneously and results in the forest itself -- its called when the successional growth reaches turn timer -- it may be a bit of a relic from this mod's ancestor, but in the sense it's been working for years. Fire and smoke work differently. But there's no obvious reason why this would occur, especially only sometimes... Unless it's your game DB.
It has the column RemoveWhenComplete and CreatesFeature both enabled -- ie inherently via its DB definition it should never sit complete on the map like this.
Assuming the engine/dll itself isn't messing up here, it must be somehow a DB error. Again mod load order change between save/reload is the most common culprit for DB error, if you're not changing anything in the mod menu, next most likely possibility is you may have a mis-behaving mod from steam workshop, as these are known to behave unpredictably sometimes, though its a pretty obscure chance tbh.
Here's the test you need to do next time this happens (specifically either you see a 'steady state forest/jungle' stuck on the map): save your game, open firetuner, and try to spawn one of these exact same improvements. The plot should instantly convert to forest/jungle if you do this; if so we know with relative certainty that the stuck plot is somehow glitched in the DB, and you'll have to investigate what on your system could be causing this -- if the mod loads sometimes correctly then it's capable of loading always correctly. On the other hand, if the firetuner-spawned improvement doesn't change to forest/jungle instantly, we'll look at next most likely possibilities, but will need additional context if you can identify any, any mods that affect plots or improvements, any events of any kind that may have occurred in these plots, etc.
I'm running v43 on VP 4.16.4 if that matters
I don't want to say this is it for sure, but its highly likely. I don't recall any of the table changes affecting things in this mod, but all recent dev was on 4.17+, and many table things changed in that version. I'm not sure this is it, again didn't notice any changes affecting things here in 4.17 update, but its the conclusion for now. Nothing else broken in DB? No other text missing etc.?
edit: solved, see below