This seems like the issue Philistine is suggesting. I just tested this out and its because you dont have enough money on hand. It will default to whatever you are holding.
Edit: I will leave this open and confirmed as I have tested this. Someone will get to this.
There is also a related issue with the Withdrawal panel in the Vault. It will not allow you to edit the Withdrawal numbers without the cursor advancing to the end of the numbers.
You don't need $10M on hand. You need more than the cost of 1 point. So if you want to sell 5 sets of 500 points each, priced at $70,000 per point, you need at least $70,000 on hand.
Still a pain, but you don't have to have millions on you to list points.
This was fixed once, for about a week, and then started happening again.