I saw someone in chat saying they were using tpt to get inside of peoples bases, I'm also seeing them in a stone wall right now...
http://prntscr.com/rqjyj4

When nivex added the TPT command you could literally TPT to anyone, same clan/team or not, and it would get automatically accepted. I've disabled the command since, but that was suppost to be fixed.

Merged post

As for the people inside the External Wall, you should disable Offset TPR Target.