Hey! This one is an odd bug, and kinda tricky.
Do this: turn on guardian, set floor height, turn off guardian. Launch the program , align your anchor and load into your space. If the cubes aren't on the ground, turn off program and just load it again (I don't know why, but it seems to load in at the height of the previous time you played, not the current height setting.) Shrug. It usually works the second time .
Then there is a potential that, the very first time you did the setup, the floor was badly out of alignment and so your initial setup locations are actually all too high. This can suck, you can adjust floor height in settings but it probably won't help you get things lined up correctly.
Try the set floor/load/turnoff/load again.
If no, respond back and I'll see if I can think of another solution. Maybe I can put something in the next update .