I think it has to do with the Riot servers attempting to limit data sent to the client to only essential information in order to prevent extra bandwidth use and potential cheating.
I notice that sometimes when I walk into a bush and find a pink ward or zz'rot portal, it won't pop into visibility until almost a second after entering the bush. Also, when a stealthed champion appears, they'll be able to attack me with impunity for 0.5 seconds or so before my game realizes that they should be visible.
I believe this is because it works like this.
- When I am outside of a bush and do not have visibility inside of it, my game client does not possess data for what could be in the bush
- I walk into the bush or gain visibility inside the bush, and my game client sends a request to the server for data on what is inside the bush
- The server checks if my request is valid and if I have met the requirements for seeing whatever is in the bush
- The server sends the requested data to my game client
- My game client must now render the models for whatever was in that bush
- Finally, I can see what was hiding in the bush
So, there is sometimes a noticeable time lapse between step 1 and step 6 which creates the issue. It can't be easily fixed without other repercussions though, because if we take step 2 and 3 out of the picture, then cheaters could develop hacks to access information loaded in their game client to become aware of stealthed/hidden objects before they should be able to.
For the health bar issue mentioned in the original post, I think it's the same issue at the root, but that particular data is probably withheld until scrolling the camera node as an attempt to limit the bandwidth used to transfer data by withholding data transfer until the data is considered needed (ie., when it is requested). So that case could potentially be fixed, but it would use up extra network bandwidth, so it might be better to leave it as-is. It may also be as an anti-cheating measure so that you can't use some sort of screen/map hack to view the entire game map at one time.
