Platform, device version and operating system
ios/pc
Screenshot or image
NA
What you were expecting to happen, and what actually happened
When in game and have a troop clicked, the cast button is grayed but the match goes at 1x speed rather than 4x speed.
How often does this happen? When did it begin happening?
every time i goto the cast screen.
Steps to make it happen again
Start match, click cast, game slows from 4x speed to 1x speed.
Is this your first time opening Gems of War after the v3.4 pet update? I had that exact same issue with the graphics quality, mana display, and speed being switched back to defaults when I deleted, reinstalled and re-linked my account on the Apple iPad.
However, once I edited the Graphics Quality back to my preferences, the changes were saved. If your changes ARENāT saving then the Devs will have to look into it, though.
Some of my battles start with apparently slowed animation but that can also be due to server and device (memory) lag, perhaps. Try quitting and restarting whenever your iPhone/iPad game develops judder (jerky animation); that seems to help when this occurs for me.
Hope this helps a bit.
I did everything you said and it still is slower.
Another possible factor:
In January 2018 an emergency firmware patch was released to fix a massive security flaw found in all Intel CPUs made since 1995.
Fixing this security issue unfortunately has caused significant speed slowdowns of ~30% in games and apps everywhere. The newest reboot of Gems is possibly likewise affected, especially if you are running it on an older device. 
The issue described is something that I believe everyone is experiencing.
3.4 introduced a new feature which allowed the Cast button to automatically light up green when itās ready, once the opponent is done casting.
For example, take this mock battle Vs. goblins.
You match 3 gems and then your opponent casts Princess Fizzbang which explodes and begins the dreaded Goblin loop. While your opponentās battleās animation is still going on, you can click on your own Dawnbringer (or whatever troop) which will then bring up the screen which shows the detail of that troopās spell along with a grayed-out āCastā button at the bottom. Once your opponentās cast animations have finished, the Cast button will turn green and you can hit it.
At THAT point (while you are waiting to cast) is when the opponentās animations which are happening in the background slow down to 1x speed.
Bug is still here. Game not respect animation speed settings, if āCastā window is open, and uses 1x. Very noticeable, as I am using max now. Same is true if I call āOptionsā window. But āChatā it seems free of it (itās hard to tell though, as chat covers all screen).
This is one of those grey area things between a bug and a feature.
This happens on purpose due to technical reasons.
Just because it is grey area and not explicitly a bug I think Iāll move this thread to the feedback section as itās not something I can create a bug report for but we donāt want the feedback to fly under the radar.
I keep my initial position (other post), this is a bug. Itās boring to be in x1 when we run x4, just because weāre waiting to cast a spell. The 4x is a must have.
is it possible to explain further Iāve always been confused by that as well but Iāve just waited until it was my turn instead of making a bug report/forum post since I knew there were most likely bigger problems to sort out
I like to preload my casts. Especially now that they nerfed gold.
What I do is use a controller. You can hold the left shoulder button to select all your troops, then click the corresponding button when its your turn. It doesnāt slow down when you do this.
Theyāll probably make this illegal now knowing you donāt have to deal with stupid āfeatures.ā There is no grey area here, its intended to slow you down.
@Tabu not at all, I think itās a good idea if you want to play for speed and recommend it to players looking for a faster way to cast on PC 
@thelastdragon Iāll get back to you on that
That is good to know, Thank you.
@thelastdragon I spoke to the team more about this and unfortunately, this is one of those things we canāt go into more detail about.
Iāve asked the team to consider investigating this in the future, but for now all I can say is due to technical limitations the game runs slower when a Troop is selected in battle.
There is also a limitation to allowing the enemy to proceed with their extra turn, it will hang until you deselect the current troop. Iām sure this is under the same umbrella, but no one else has brought this to attention.
That is the coolest gow gif ever. Now we need one for āSoon ā¢ā