Problems with shadowy disguise?

aco5712

So i havent played on my NB for about 2-3 weeks, so i jumped on with a friend (who is also a NB) and we tried to go ganking. I ran shadowy disguise, idk if he ran the same or dark cloak but we both had it on our bar. We ran into a huge amount of zergs. Usually if you see the zerg heading to your location you either stealth out of the way or if thats not a option you cloak out of the way. I did this plenty of times 2-3 weeks and never got caught or seen. But yesterday, idk if it was due to lag or whatever, our cloaks would stop working as soon as someone got close/ran over us. He said it could be because of mage light but after he left, i ran into players that didnt have magelight on and stil the same thing happened. I see him coming, i repeatedly cloak about 5-10 metres away, i get detected and cloak is removed and then i get rolfstomped by the zerg following. Anyone else having this problem or is it just me?