Oyster in London works like this too so I’ve heard. Some terminals (e.g. those on buses) are offline until the terminal is docked and connected to the main centre.
The Helsinki metropolitan area public transit system "HSL" used to be like that.
Bus passes were first mifare and the DESfire after some upgrades, but the readers in the busses contained the transactions and worked offline.
If they got filled up the the standard practice was free fares. :)
If they got filled up the the standard practice was free fares. :)