Some Rogues might have noticed this already, but Necrotic Core (Tactician ability) has been temporarily disabled due to players using it to prevent the other team in warfronts from capping objectives.
Basically a Rogue was able to place Necrotic Core down on an objective which ticks damage in the area, preventing the opposing team from channeling to capture an objective like a flag, capture point or to destroy a core. The Rogue would then run out or stealth out to prevent themselves from dying and then teleport to the objective to drop another Necrotic Core once the previous one times out.
Once the servers are updated again (unknown ETA), Necrotic Core will be changed so that it only interrupts players on the first tick of damage. The only way to be interrupted again is if you leave the AoE and re-enter it.
[Source: CM Ocho]
RiftGrate 
…I’m sorry, what? This has been a thing for a very long time.
It has, but it only recently hit the Rift PvP forums so probably wasn’t really brought to the devs attention until then.
the NTE mastery has extended the duration from 15s to 30s, so it made things worse. They should just make the core targetable and killable like the defiler beacon.