I had some problems on 9/14/15 in Natimbi. Buffs and heals would not take hold. Mobs would die and I would get the exp message but they would appear to still be alive.
When I zoned out I noticed all the buffs I had casted did take hold, they just did not appear. By then the mobs that were kills appeared as corpses but I could not loot them. A new mob would spawn on top of the dead one.
I couldn't heal my bot. Heals would not take hold on him. I had to zone out to heal him.
This was not consistent though: sometimes it would work fine, while at other times the problems as listed above would happen.
I checked my internet and I had a strong connection all the time. I also rebooted my machine and made sure my patch is up to date.
This was a cleric with a warrior bot.