I'm not really aware of this rule because I did not experience this during CBT. Thanks to "MissFly" for sharing me this thing during our party at LM1.
Kindly find more details below:
1. Tank aggros a mob that takes long to kill, such as Tranquilla.
2. Healer uses a low-level heal on the tank after 5 seconds.
3. Healer sits down for faster mana regeneration.
4. Healer uses another low-level heal on the tank after 1 minute and 10 seconds.
Even though in steps 1 through 3, the healer never really takes away aggro from the tank, but after step 4, they have generated an infinite amount of aggro on the mob. This is the result of the 1 minute rule. It is impossible for the tank to pull the mob off the healer at this point using skills. The only way the healer is de-aggroed is if either the healer dies, logs or moves out of the follow range of the mob.
Intentional triggering
Sometimes people intentionally trigger the 1 minute rule. Example: a 50+ party aims to kill Abhuva. A high-level (120+) character outside the party could help with this by triggering the 1 minute rule, allowing them to tank without doing any kind of damage or skill on the boss. This results in no experience or drop penalty for the party, and, if party leadership is followed carefully, no deaths.
Source: Click here
