Poker apps freezing on iPhone when switching between tables—any fix?

Lately, I’ve been having an issue where my iPhone lags or freezes when I switch between multiple tables on poker apps like PokerStars and PartyPoker. Sometimes, the app even crashes, and I have to restart it, which is really frustrating, especially in the middle of a hand. I’ve tried closing background apps and reinstalling, but it still happens.

Is this an iOS issue, or could it be something with these apps? Has anyone else experienced this, and is there a fix?