Originally posted by Soma:

I had a similar problem. Had a portal in mistlands that was buried after the update. The portal stayed in tact though underground. If I use the portal I show up on the ground somewhere above I believe. So its basically a one way portal. I thought of digging under to look for the portal, but decided to keep it there hidden to trick friends :+)

I have a feeling this is what happened to you. If you make it back to base and the Mistlands1 portal is still active then that would confirm it is the same as my world, you have an active portal underground and when you use it it pops your character to the surface.

I managed to teleport back to base by collecting the materials needed (luckily all were nearby. The hardest was Fine Wood), creating portal to one of my spare portals, then creating extra buffer portals to test while carrying enough materials to create a new one if I got stranded again.

When I got to my Mistlands1 Portal in base, it was offline. So mabye it was a one time thing?
I was able to connect it to the intended target for the portal so I'm glad.