Hmmm, Damian uses vi (or a modern imposter), doesn't he? So, I guess you copied some vi macros and/or settings from him that turned tabs into space.

Next time, if you really want a tab, enter it as ^V^I (control-V control-I). That should bypass any macros written by someone who isn't an evil genius.

Oh, wait. You said Damian. He is an evil genius.