Full description about the network icons like yellow plug
Will appear when your ping is high. A yellow latency icon means your ping is high enough for additional validation steps to be triggered by the server (around 100-140 ms of ping). These additional validation steps come into play when treating your shots, and determining whether or not they are a hit. You might notice some of your hits are not registering. Having a high ping also means you could encounter unpleasant situations such as dying behind cover. A red icon means your ping is bad (around 400-500 ms of ping). Being in that state for a long time could result in player being kicked from the game server. When the latency red icon is visible, almost all of your hits will be rejected by the server. This is intended.
The connection icon appears when you are experiencing packet loss or latency instability (for example, when some of your packets are being redirected on another internet route). When this icon is triggered, you can experience rubber banding, hits being rejected by the game server, and abnormal induced latency. The probability of experiencing those situations is far higher when the red icon is visible.
FPS or Update rate icon appears when your frame rate is dropping or is unstable and the number of packets sent by your game client to the server is not high enough. You might experience hits being rejected by the game server and abnormal induced latency (this latency is induced by the game server to prevent other players from seeing your character stuttering). You could also experience rubber banding when the icon is red.
The host icons appears when the server is experiencing issues and is unable to preserve the stability of the simulation. All players connected to that game server will see the icon appearing at the same time. When you see this icon, you can experience rubber banding, abnormal latency or hit registration issues. Those situations will be more noticeable if the icon is red.