When using billboard material on an object, the only thing that can be changed during runtime is its location, changes to its scale won't do anything. Same if trying to assign a different material.
Assign a different material is not a problem, I just had the wrong setup.
Scale is an issue, I have attached an example with two planes one set to billboard and the other one not, both have same trait attached to it: on click change its scale, only no billboard plane changes.
@luboslenco where is billboard script kept at?
@BlackGoku36 searching for billboard in armory and iron folders should display all the references to it (python UI, shader gen and passing uniforms).
Fixed at https://github.com/armory3d/iron/commit/4b03e47e77aa9dfeb271822da7d6cd0991bfa5a7, thanks for report!