Hello, I would like to report a bug concerning "vehicles" using a block command and the relative coordinates (~ ~ ~)
I couldnt choose 1.15.1 version , only 1.15.2 proposed , but i m in 1.15.1

Indeed, using a command block (in Impulse, unconditional, need redstone), cloning in Masked Move of a structure generates a very compromising bug: Cloning is repeated endlessly, at least up to the borders of the map.
 
After many tests, I determined how to make cloning work without this bug. But there are still a lot of cases where this happens.
 
 
If the command block is on one of the edge of the parallelepiped, in the clone function I would have this model: / clone ~ x1 ~ y1 ~ z1 ~ x2 ~ ~ z2 ~ x3 ~ y3 ~ z3 (I put the command block a the height of the second point constituting the cubic rectangle, y2 is absent, there will be just the "~")
 
It works, the structure moves as I wish.

However if I have to fill all the relative arguments (so if the command block is found not stuck to one of the walls of the volume of cloning that we are creating), The bug occurs, The structure clones very quickly to infinity. (and destroy everything in its path)
 

 
 
There seems to be a problem in cloning, the command block keeps the signal active, and repeats the process.

I tested various possibilities, the problem returns when the block is not glued to the walls of the Cube clone has performed.