World copy abuse?

I thought this was normal at first, but basically, i have a copy of my friend’s world on my computer(i think it happened when he logged into steam on my computer). If i load up solo, its an old version that’s back before we even defeated the elder. We kept playing on his version(mine doesn’t update), now we’ve defeated the bonemass and need to find silver. After searching every mountain we could find, only 1 silver deposit has shown up. I had the idea to pull a valorant, and stand on the silver deposit in his world and then load up mine. When we joined, we were standing upon a fresh silver deposit and were able to pull a valorant and mine 30 extra silver that we shouldn’t have had (my pickaxe broke).

We then walked to where our outpost would have been, swapped servers back, and tada, more silver.

We also learned the hard way that logging out makes you lose your frost potion.