Modal only showing after the second click

Could you use v-on:click="details(row.item,row.index,$event.target)" instead of @click.stop="details(row.item,row.index,$event.target)" ? or I'm getting everything horribly wromg :)

You should have solved the problem, but for future attempts it's my opinion. I had a similar problem. In my case the problem was the v-if used to initialize components inside the modal. I belive if you change the v-if to the h4 and b-container tags will work.

Review your code and i am not sure but you can try

details (item, index, button) {
  this.modalDetails.data = item
  this.modalDetails.index = index
  this.modalDetails._id = item.content._id
  this.$root.$emit('bv::show::modal', 'modalallergy', button)
  this.$root.$emit('bv::show::modal', 'modalallergy', button)
}