Teamwork deleted my columns

[4hotshoes]

I created a segmented column and placed several then selected "Send Receive" and all the columns disappeared. I was puzzled. I tried it again, same thing. I quit and restarted the computer, placed the column and Send and receive deleted the columns again. I placed a wall and Teamwork did not delete that. The problem must be in the column. At first I thought it was the server.

It turns out that when I created a point on the top of the column to make a pyramid shape, I put a zero value to make the point. It did not say I should not do that. After I put in a small value it did not delete the column. 

I have mistakenly put in zero values before and the entity was never deleted.

I don't understand why it would simply delete the columns rather than generate an error. I think it may be a bug?