I think it is a bug. Steps to replicate:
1. Create a node
2. Create an alert and trigger it
3. Reset trigger condition (reset alert)
4. Rename node
5. Trigger alert again
6. Go to alert landing page. "Triggered by:" on Alert Status Overview would not be updated
7. Go to node: In Active Alerts resource "Object Information" would still show old name
I have tried to toggle Alert's Enable (On/Off) - issue still persist. I guess I will need to recreate alert for this to be cleared