I was researching over 5k per turn with around 15k labs and then I was suicided with missiles and SRs by someone who then deleted their account. I rebuilt my labs to about 12500 but the tech per turn never went back up. I'm now researching 866 per turn. Is this because I have very low population now? I'm down to about 11k but I never thought pop influenced tech per turn. This is in express.

not a bug.

production (incl income from taxes) is tied to population and when a portion population dies/leaves production goes lower and lower and only using turns recovers from that outside dropping land to get max pop per current land.

You're right. Thanks. Never noticed that but it is slowly going up each turn.