Simple example:

GetGame().GetCallqueue().CallLater(fn, delay: 300 * 1000);

// After few seconds (Until it reach 0)
t1 = GetGame().GetCallqueue().GetRemainingTime(fn);
GetGame().GetCallqueue().Remove(fn);

// After few seconds (Until it should reach 0 if Removed wasn't called)
GetGame().GetCallqueue().CallLater(fn, delay: 300 * 1000);
t2 = GetGame().GetCallqueue().GetRemainingTime(fn);

Results in t2 != 300 * 1000

Reproduction using entity component:

1. Write component:

2. Open any world and add it to the GameMode;
3. Start world - it starts printing 0 remains until Finish()
4. Execute (by Remote Console):

TAG_Component.GetInstance().Start(15);

It starts counting from 15 to 0

5. Wait until 10 seconds left;
6. Execute

TAG_Component.GetInstance().Stop();

It still counting...

7. Wait until 5 seconds left;
8. Execute:

TAG_Component.GetInstance().Start(10);

First, it counting from 5 to 0. When it reachs 0, it jumps to 4 and continue counting to 0. And only after this calls Finish()

Looks like by calling Remove you just set Removed flag inside Callqueue and not remove it actually, and GetRemainingTime not checked for this flag and returns time for this entry until it is timed out