spawn issues - lag maybe?

On 24/04/2011 approx 2200hrs - 0300hrs gmt time.
I experienced some weird issue whereas my toon was running dungeons with a friend , he was killing mobs no problem, however - on my device i could see no mobs only the exp and hit values above his head, i didnt appear to be taking damage nor cld i attack the invisible mobs, however , when i logged and relogged my deaths count had jumped up 5 or 6. Is this merely an issue thatbis possibly Lag related - although Ping was around a nice low 280-350 range?
Htc Desire HD Android 2.2

Anyone else had this unusual glitch (funny to watch mind) ?