1st bug (Full hull repair with no cost)
1) Ship has sustained hull damage, but no broken parts (lets say 50% hull)
2) Enter build mode
3) Place a huge stone/armor block
4) Ctrl-Z or remove block
5) Ship now has full hull with no material cost
I'm sure this is not an intended mechanic and should be fixed for the sake of the players' gameplay experience.
Some suggestions to fix this:
1) Fix this game mechanic directly, for example, preserving the percentage of hull no matter what modifications to the ship is made
2) Only allow editing of ship when hull is more than 90% hull? and maybe only allow building/repairing when in a neutral zone or repair dock/shipyard
2nd bug (Crew hiring bug)
1) Ship docks at station
2) station has, lets say, 57 engineers available for hire
3) Player sets the slider at, lets say, 45 (slightly lower than the maximum available for hire
4) By clicking the "hire" button fast enough, it is possible for the available crew for hire to reach a negative value (eg, -7)
5) Once the player hires any negative value of crew, work force becomes a very big number (almost infinite). Stack underflow problem?
At this point, the player's ship will have unlimited workforce for engineers, but because the number of engineers he has is still a positive value, restarting the galaxy will fix the problem, however, in a few more steps he can break the game
6) Dismiss all engineers (possible because crew amount is still positive)
7) Hire negative value of crew from the station
After step 7, the number of engineers on the ship will become negative, and dismissing anymore engineers will make the negative value even more negative. Crew workforce for engineers is near infinite and will persist even after restarting galaxy (actual crew amount is negative as seen in the "transfer crew & cargo" window, but shows a very big value in the "Ship" tab when pressing P