If Castle Crashers is trying to patch anything else besides these bugs, they may be trying to roll those all into one. Also, the approval process for XBLA games might be slower - since they're lower demand/lower userbase.
The way xbox patches work in general is that the developer only gets one patch for free. After the first patch, you have to pay MS a fee if you want to patch the game again, as a disincentive to release sloppily coded games on consoles. Thus, Castle Crashers' producers may have decided to wait and use their one free patch when they have substantive content to update as well as the bug fix, whereas valve probably figured this issue was glaring enough that it needed to be fixed right away.
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