Quoting Rhonin_the_wizard,
Working as intended, some Artifacts have repeatable upgrades.
Thanks Rhonin,
If so it's over powered. Once the planet is set up then it's 3 Thulium per turn for 2000 shipyard production anywhere you like - so if you capture a planet you can rush a shipyard for 600 and then get a huge ship the next turn.
MindlessMe you might like to consider redressing the balance somehow - please not too drastically everything in this game seems to swing wildly every time there's a patch.
Cheers,
Jon