When a player will telport to another world their game-mode stays the same.
For example: Player from a creative world goes to a survival world by walking through a teleporter. Their game-mode will still be Creative when it should be Survival.

You sure they don't have the ignore permission? https://github.com/Multiverse/Multiverse-Core/blob/601f457e6f976d1884be1f216b11ebbfd49043eb/src/main/java/com/onarandombox/MultiverseCore/MVWorld.java#L380

Hi there. We're cleaning out the issue tracker since we (mostly me) have mistreated it.

This issue does not have enough information to warrant keeping it open, so I'm going to close it. If you're no longer interested in getting it solved or you already found a solution, great!

If you're still experiencing a problem, please have a look at Reporting a Bug and reopen this ticket! Thanks!

You should also make sure you're running the latest spigot code as well as the latest Multiverse-Core and Multiverse Plugins.