When it begins pets de-spawn. And I spend most of the 10 second countdown resummoning mine, not wanting to waste the fast cast version incase something goes wrong in an early pull.
Why?
I get that mythic wants to prevent people pre-potting before the timer but this? It’s taking a standard feature of a pet class and making it an irritation. A minor one, but an irritation never the less…
You didn’t read the OP.
I want back the fast summon that demo had.
To add to that, cast that BEFORE the keystone starts. Like right before.
You have the buff after the keystone starts and you can just whip out whatever pet you like! 
It will also reset the cool down when the keystone starts
I just whistle on my alt and all done
Oh I misread it woops.
Sure didn’t!
That works. Which is good but… still. ^^ It feels like a faff for something that shouldn’t happen. Thanks tho!
Oh it’s all good! I misread the original OP 
Use fel dom just before the key starts the buff will carry over and fel dom will reset
Not really. Because your method doesnt waste the cd. I was going to type the same.
As for the OP on why. Some cds are pets and summons and they limit the cds that work this way.