Custom buildings breaking on interaction

Summary:
Created a custom building, selected floor, selected walls, selected second floor (one half of roof), made stairs, selected second floor again (Rest of roof) went to add walls to the second story and it only went on the 2nd half. couldn’t delete anything in the building, tried to add a door upstairs instead and work with it, but that didn’t work either.
got annoyed went to delete building, made deletion noise but building stayed.

Can no longer build on that spot as the building just sits in the nether constantly.

clicked submit bug and it produced this code
6f4e7eec-5a53-11e6-97cb-408d5ce310e9

Steps to reproduce:

  1. build custom building
  2. hit finish building and delete

Expected Results:

Actual Results:

Notes:
Im not sure what caused the bug so i cant really help with the reproduction but it has happened twice tonight now.
Attachments:

Version Number and Mods in use:
no mods - release 593(x64)
System Information: