RdpxDecayingBonds::decreaseAmount() does not decrease the bonds amount, but replaces its value. This is misleading and can lead to integration errors if they follow the Natspec: amount: amount to decrease.
RdpxDecayingBonds.sol#L144
The only call to the function in the current scope is performed on the RdpxV2Core contract.
In this case the amount passed to the decreaseAmount() function is the expected decreased value, so the whole system works as expected.
RdpxV2Core.sol#L645
Nevertheless, this can lead to future errors.
Change the name of the function to a better name like updateAmount(), or refactor the function and its calls to match its description.
