If you truly think this is a bug (it isn't), then put in your issue at Connect and let Microsoft know.
Now, the reason this is not a bug is because initial_size <> default_size - and the only way the initial size is defined is either:
1) When the database is created...
2) When the size is changed using DBCC SHRINKFILE with the target_size parameter.
Jeffrey Williams
“We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”
― Charles R. Swindoll
How to post questions to get better answers faster
Managing Transaction Logs