I'm currently seeing that none of the games I start have mining productivity as a researchable tech. It seemed to start a couple of days ago, at that time I played with omnimatter and sosciencity, not sure if these are the cause.
Could sosciencity affect mining productivity in a way? that even when you start a new gameplay session without that mod it is not restored to the default? Just asking as I'm currently puzzled why its no longer working .

thanks for any feedback you can give.

Hello, Sorry for the late answer.
Sosciencity doesn't touch the mining productivity techs in any way. What might have happened was that some mod hid these techs. This state then persisted in the savegame. You might be able to resolve this with this command:

/c for _, force in pairs(game.forces) do
force.reset_recipes()
force.reset_technologies()
force.reset_technology_effects()
end