When minting OSTa it the system only lets me mint 90% of my OSTa, apparently to keep a reserve for GAS. I would suggest that rather than forcing the customer to keep this 10% the system should generate a warning and let the customer decides if he wants to keep a reserve or not and how much.
I manage around the issue by minting a second time 90% of the balance but it means new ETH network fees when staking.
This is the current implementation of OST KIT⍺. We do have an explanation article in our help pages:
building up on that think there should been a link too to explain about the cause and effect of staking gas and how it effects the token.