Buggy I guess. I mean you can go and spam nightfallen buffs for 50 mana but its very annoying having just killed 8-10 mobs and not being able to mine them.
You could always get the max mana up, that can alleviate you maxing out so quickly. You can also dump mana into the world quest that pops up every couple days for withered training you can dump up to 2k into that to keep your mana down.
My cap is at maximum 2000 and I always do the withered training @ 2k. Still I cap out incredibly quickly from farming. This wouldnt be a problem if they simply let us mine living without having to pick up the mana, also very annoying to have the nodes on the map while there is nothing there but mana.
Have you considered farming less and not collect the mana unless you actually need it? I understand your plight, but it's so easy to reach 2000 mana that there isn't any reason to keep a full stock of it (especially when situations like this occur).
Well I need to collect the mana from the corpses if I want to mine it, no going around that. Same with the nodes, if i dont collect the mana it takes quite some time before they dissapear from the minimap. Farming less? Need the dollars man