min() vs median() for string columns

When I try to get the min() or the max() of a string column (whose type is CHAR(2) ) - that works; but when I try to get the median() - I get an error about not being able to convert a value (say, 'AA') to type bte. Is this intended behavior? A bug? Perhaps something I might be doing wrong? PS - In case it matters: * I'm using v11.23.7 * I'm using the USDT on-time flight data, in a DB you can setup using the script here: https://github.com/eyalroz/usdt-ontime-tools