I think I know what happened.
Sometimes the server is badly out of sync, making you and the other player not see the same things. While you took damage, to the other it must have looked as if you had taken none. I've seen that a couple of times and it is a real prestigekiller. When someone starts shouting in the ingame chat system about a player whose hull didn't seem to be damaged, i usually tell them that this is due to a server synchronization error.
I have seen it the other way around as well. Another player seems to take damage, while his shields are up. I had someone frantically shouting that i took heavy damage with my hawk in a planet run, while my shields were nicely in yellow.
There are loads of other server sync errors, like the infamous no-power bug, the I-have-to-keep-bringing-up-my-shields-because-they-disappear-from-time-to-time bug, the player-shoots-something-which-I-cannot see bug, the i-cannot-damage-that-AI bug and the lag-killing bug (on the last one: due to lag, the server fails to update your hull status, which means that you are ripped to shreds even though your hull is in yellow
).
Aenigma