Some keys are missing from transifex...
Just checked. All three keys you mentioned above are there, both on transifex and in the generated language packs on virtuemart.net. Probably you should use Joomla's 'Debug Language' to find out what is wrong with your language files.
You're right about transifex, I searched for it in wrong file (admin, not frontend)
I found COM_VM_ST_SAME_AS_BT but it's already translated to Hungarian at Mar 20, 2018 5:50 PM
I re-downloaded the language package from here:
https://virtuemart.net/community/translations/virtuemart/hu-HUand checked the key, and found this:
; COM_VM_ST_SAME_AS_BT="Same as Billing address"
Also checked the last modification of the laguage files and it's Mar 13, 2018 7:50 AM
So it must be something around syncing from transifex to virtuemart.net