1.7.2 Mobs/Celia willingly open doors bug

[GlassGo]

SO, I was fighting some shitty bone giant from coffin in Celia crypt, mob tp me out and then I saw that someone opened door to Celia room.
Maybe it was that bone giant, maybe it was Celia.
I continued to fight with that bone giant because untill you trigger Celia you are ok, rigth?
Wrong. Bone giant tp me again, and when I went back to him, there was Celia.
My char died for absolutely nothing.
Why such bug still exits?
Is it THAT hard to restrict that door interaction only to PC?