I have found this also. I think problem is when a prepare function is executed. I have SQLite manager like program that must detect if statement will return data or not. So I call prepare to get column count. In this case with returning I get the same result (rows inserted twice). Maybe PHP driver is doing the same. I did not report this I think no one will care because as you sad in CLI shell (I tested also) this works without a problem. So this is not a bug just should not be used with prepare.