I cannot use the building wand to place Light Blocks (minecraft:light).
Edit: By cannot use i mean i cant place them with the wand like normal blocks

This is caused by the special behavior of light blocks. They only show a hitbox if you are holding one in your hand (same with barrier blocks).

It might work if you have light blocks in your offhand, but I have not tried that.

If that does not work, you can use WorldEdit instead.