No, that is unlikely. Since cash withdrawals are online transaction, I don’t believe anyone would get more money out of an account than it holds. There is no overdraft allowance. Having said that, offline transactions could cause a negative balance (if a card is used with an imprinter). I have no idea how this would be handled by Revolut.
Maybe the ATM uses different exchange rates to show funds in USD that are held in USD, GBP and EUR in your account. This is what Revlut’s FAQ say:
The ATM will display a total of your GBP, USD and EUR balances in the local currency. For example, if you check your balance at an ATM in Thailand it will show a total of your three balances in Thai Baht!
Pending transactions reduce available funds in the app. I have no idea if they are factored in at an ATM, but my guess is they are.
Who checks funds at an ATM anyway. You’ve got a nice app for that