the vue sibling component passes a value, but when receiving the value, there is a problem with the this pointing?

a.vue

import Bus from "../../utils/bus.js" //vue 

export default {
    components: {
        baidumap,
        bmView
    },
    data () {
        return {
            zoom: 10,
            address: ""
        }
    },
    mounted () {
        this.createdMap();

        let that = this;

        Bus.$on("addValue",function (argument) {
            console.log(that)

            if (argument) {
                that.address = argument.ci_name
                console.log(that)
            }
        })
        console.log(this)
        console.log(that)
    }
}

b.vue

import Bus from "../../utils/bus.js"
export default {
    data () {
        return {
            proshow:true,
            cityshow:false,
            countyshow:false,
            townshow:false,
            proArr: [],
            cityArr: [],
            countyArr: [],
            townArr: []
        }
    },
    methods: {
        selectpro (item) {
            if (item.ci_id == 36) {
                Bus.$emit("addValue",item)
                this.$router.go(-1);
                return;
            }
        }
    }
}

the this output in a.vue points to
][2]][1]

bus.js vue

Why is it that their _ uid is different and the address data has been changed in the instance with _ uid of 3 and the address data has not changed in the instance with the uid of 50?