User blog comment:AgentG231/What specifically is the bug in the Animus 1.28 that made Altair can't swim?/@comment-1888015-20130427175350

The inability of Altair to swim was never a bug.

It was that the developers of AC1 were facing time constraints, so they chose to call his inability to swim as a "bug of the Animus", simply because they couldn't fit in swimming animations, sound effects, and the like to the final product.