[Vuejs]-Vue doesn't update props data on array change in for loop

Use <b-card v-for="(campaign, i) in settingsData.campaigns" v-bind:key="i"> and use campaign instead of settingsData.campaigns[i].

This means that you are iterating over the Array/Object: settingsData.campaigns. campaign will be the current campaign and i will be the index of that campaign.

You are trying to iterate over the property length instead of an actual Object or Array.