Did you try printing out the variable? If the issue starts occuring after these changes, it must be due to the variable not being set to true. You can check this by plugging a print string node after we set it to true. Now if that’s the case, I got a guess on why that’s happening.
It might be because the Event Begin node doesn’t run anymore after the first frame, therefore there’s no execution flow that can trigger the Play Montage node’s on completed pin. If I’m right about this, you can simply solve this by triggering a one shot delay that’s the duration of your spawning animation after your Event Tick node. You can achieve that by getting a branch node, plugging a delay node into it’s false pin, setting a bool type variable to true after the delay, plugging that variable into the condition pin of the branch node, and connecting the rest of the code that you execute after the Event Tick into it’s true pin.