[Vuejs]-Memory leak when changing a value that indicates an index in a computed property

It’s hard to tell with the currently provided code, but I suspect that this.correctAnswersForLevel1 etc are also computed properties. This would mean you get a circular reference which results in an endless loop.

Aside from that, the code contains wrong references:
this.correctAnswers['1'] is not the same as this.correctAnswers[1] as this compares strings and numbers with each other.