First, Blizzard has fixed the bug with the Ultralisk's building attack and the application of splash damage, which made repairing buildings impossible for Terran players. This was introduced in patch 1.1, which changed the way Ultralisks attack buildings. In some late-game situations, this made it too easy for Zerg players to destroy Planetary Fortresses and other Terran buildings. This match from the GomTV GSL has a few instances of this bug in effect.
Secondly, bypassing the built-in delay for workers returning minerals has been deemed a bug and has been removed. By manually telling workers to mine minerals and "return cargo", players were able to see a 7% bonus in resource collection rates. Top level players have been doing this since the exploit was found as they have spare attention during the beginning of a game. It is now gone.
The full patch notes, including a few other bug fixes, can be found below.
StarCraft II: Wings of Liberty - Patch 1.1.1
Fixed an issue where Ultralisk cleave range was being unintentionally extended by larger targets. Fixed an issue where the Phoenix's Graviton Beam was automatically canceled if you used it just after the Phoenix reached 50 energy. Fixed an issue where queuing Return Cargo on a worker would cause it to ignore the built-in delay after it finished gathering. Fixed an issue where players watching older replays or saved games would experience stuttering. Fixed an issue where some Mac users were unable to join games properly.
The patch should be live on Battle.net and can be obtained by launching StarCraft II.