I have a free shipping price rule which is configured like this:
If we are talking for Magento CE 1.9 and above, the code is corrected as long as the database is concerned but you might encounter the same problem! If so, then there is another cause.
One also usual bug is * user not being able to update the cart quantities* or users not able to login. This has to do with formKey and the answer that was given here.
Apparently, the same solution fixes the problem of vanished shipment or payment method after applying a coupon, that we are discussing here.
Hope this helps users of newer versions...
so be it - manemoi