WCH2 Charging Hub: LED indication

[Mike Shock]

I want to ask the experienced owners of the WCH2 Charging Hub about the LED indication during a charging process.
In the User Guide it is written that when it "blinks green" - it's charging a battery, when it's lit "solid green" - the battery is charged.
BUT my hub first blinks green SLOWLY and after some time (~ 20 minutes) it starts blinking green FAST (in series of 4 flashes repeatedly).
Can anyone explain what it means? Does it mean that the battery is almost charged?
(When I take the battery out at this moment and place it in the Crystal Sky, it reports tha the battery is ~75% full.)

 

[Mike Shock]

In the User Guide it's also written that the indication of "alternating green blinks" means "Intelligent Battery not detected" - but I doubt it's my case.

 

[Mike Shock]

A couple of times my hub blinked YELLOW - that means that the hub / battery is too hot and needs cooling before the further charging...