me and a friend have been playing the mod for the past few days and at some point today the mod after completing a random technology did reset our current age and our progress.
i have no idea what information could be useful here to figure out what went wrong in the mod so please let me know of any additional information you might need.

me and a friend have been playing the mod for the past few days and at some point today the mod after completing a random technology did reset our current age and our progress.
i have no idea what information could be useful here to figure out what went wrong in the mod so please let me know of any additional information you might need.

Did you add mods or update them? Does this persist after researching more techs?

all research related mods im using only add new techs before Exotic industries sorts and rebalances them like the QoL research mod for example.
we only set the list of mods once at the start and then later removed the miniloader mod whos tech should not influence the age progression if my understanding of your script is accurate.
Its worth pointing out that removing the mod did not break it imediately but this occured after researching multiple technologies after the mod had been removed.
The age progression doesnt update but im not able in the save where we currently have this bug to check if researching dark-age (the age it did reset to) would fix it once the progression reaches the threshold because we already have done all technologies that give progression points.
what i can say is that technologies from any other ages we already had unlocked before the bug did not contribute to the progression and also didnt fix the bug upon completion.
so regardless if researching a tech from the age it thinks we are would fix it or not at least in our current situation we need some sort of bug fixing method that automatically revaluates which ages we should have access to in order to fix the current age and progression.
since im not sure how the bug occured i also dont know how i would replicate it in a new save in order to try out if researching tech from the age it thinks i am at would fix it, so unfortunately i cant answer that part of the second question.

all research related mods im using only add new techs before Exotic industries sorts and rebalances them like the QoL research mod for example.
we only set the list of mods once at the start and then later removed the miniloader mod whos tech should not influence the age progression if my understanding of your script is accurate.
Its worth pointing out that removing the mod did not break it imediately but this occured after researching multiple technologies after the mod had been removed.
The age progression doesnt update but im not able in the save where we currently have this bug to check if researching dark-age (the age it did reset to) would fix it once the progression reaches the threshold because we already have done all technologies that give progression points.
what i can say is that technologies from any other ages we already had unlocked before the bug did not contribute to the progression and also didnt fix the bug upon completion.
so regardless if researching a tech from the age it thinks we are would fix it or not at least in our current situation we need some sort of bug fixing method that automatically revaluates which ages we should have access to in order to fix the current age and progression.
since im not sure how the bug occured i also dont know how i would replicate it in a new save in order to try out if researching tech from the age it thinks i am at would fix it, so unfortunately i cant answer that part of the second question.

Mhh. can you send me the save file?

of course, here is a link to the save file: https://www.dropbox.com/s/gmkcmn7gyeozegl/Exotic%20Industries%20multiplayer%201.zip?dl=0