I found this too, but progressed without any problems. I mean, with out the Nice green arrow showing you where the invisible mob is, THAT would have been hard...! ;-)
One thing I did notice though was the damage calc's seem to have been out.
On my first hit I would do around 750 damage. Nice, when you normally hit a bit over 200!
Next hit would be around 550, then 350, then 150.
Then on what ended up being the final hit, the mob would appear and I would do 0 damage. Then it would die.
This happened consistently every time with that mob.
I figure at that level I would probably 4-5 hit that mob anyway, so didn't worry about it, but the damage scoring was dodgy...
It's not the damage, it is the amount of HP it has left - I started a thread about this (it is called 'help')
Saw that after I'd seen this thread and written the bit above.
'Help' is a bit generic, considering what's been going on in game lately! ha ha ha
;-)
Yah. But it catches people's attention!