Both ousgInstantManager and rOUSG uses an oracle to determine the price of OUSG.
rOUSG::getOUSGPrice:
Very similar in ousgInstantManager::getOUSGPrice but with a lowest price check.
Here only the first parameter, price is used. However, the second parameter returned is the priceTimestamp, which is the timestamp at which the price was updated. If this is old it can lead to incorrect OUSG prices used for rOUSG or instant minting/redeeming.
Consider adding a check to confirm the price used isnt stale.
