The problem here is obviously liquidity management. You could think of the vault as a battery that charged and discharged. If you drain and charge the battery

The problem here is obviously liquidity management. You could think of the vault as a battery that charged and discharged. If you drain and charge the battery at the same time, there is no net change in the charge level. Theoretically, you wouldn't need the battery to begin with. Now add time lags. Now discharge may happen before charging. The net change is zero over the full duration of the cycle, but the battery is being drained temporarily and it is changing its state all the time. If the battery is not large enough, the system will shut down. This in itself is not necessarily a catastrophe, but you will have to pay damages over the shutdown duration for the consequences of that shutdown. This will probably ruin profitability of the counterparty.