The techs_researched was initially set right, but number of researched future techs not, i.e., the civil war player lost all their future techs.
Fix is rather trivial with low risk. To stop games in 3.0.2 accumulating more techs_researched sanity problems, I'd still include this to 3.0.2.
Plan also to push to S2_6.
S3_0 autogame with a bunch of local patches (most of which are still targeted to 3.0.2, but also sanity check for #44594) reports techs_researched counter problem. This comes immediately after a message about creation of a new player (presumably civil war)