The program just does what it is programmed for: if you have auto merge and you move terrain anchors one on top of another.... they will merge! This can't be called a bug.
I find v0.6 beautiful and I can work flawlessly, you just have to be aware of what you are doing. For all the rest CTRL+Z is a good medicine in the learning process, but once you master it, it will give satisfaction.
...but I dont drag terain over terain. Like a sample I select 5 anchor and slightly drag up - about 3-5 mm. But this bug repeat nor every times and is not verry criticaly.
Yes I know how did return, but if you regularly did saves, you have only delete terain...Anglonas Anglonas Anglonas Anglonas
maybe I understand how it happens: do you work on a side view maybe?
From the result of the picture it seems that you wanted to move terrain anchors in height, from within a side view (those two on the bottom) and so you merged two anchors with the same height.
If so, uncheck the automerge option when doing that.