The thermal bulb itself is not position sensitive in relation to its process tube.
You can put the bulb in incorrect spots. It will make the valve erratic but not shut down. The liquid in the bulb is not going to go down the tube like you're thinking. You've got something else going on there. Unless it took awhile for the person to call in, sounds like it could be airflow.
That's what I thought I never saw an ice up problem with overcharge. If its still going to do it I am thinking it could be air flow. It is a mobile home furnace and I'm not thrilled with the louvered door return it seems insufficient
While possible it was the bulb orientation. I would guess that it was/is an air flow issue. Someone may have set the stat to a low temp to get a far room cooler. And it froze over night while it was cooler outside.