Angular UI-Grid filtering

Question

On my angular application I have a UI-Grid and a button to open a modal window. In my gridoptions I enabled external filtering. But the problem is whenever I enter the filter field and press enter the button(modal window) is triggered and the modal opens up. I don't have any key events inside my controller.

Here are my gridoptions for the ui-grid:

gridOptions: uiGrid.IGridOptionsOf<any> = {
        appScopeProvider: this,
        data: [] as any[],
        enableFiltering: true,
        enablePaginationControls: false,
        useExternalPagination: true,
        minRowsToShow: 5,
        useExternalSorting: true,
        useExternalFiltering: true,
        onRegisterApi: (gridApi: uiGrid.IGridApiOf<any>) => {
            this.gridApi = gridApi;
            this.gridApi.core.on.sortChanged(this.$scope, (grid: uiGrid.IGridInstanceOf<any>, columns: Array<uiGrid.IGridColumnOf<any>>) => this.sortRequests(grid, columns));
            this.gridApi.pagination.on.paginationChanged(this.$scope, (newPage: number, pageSize: number) => this.changePage(newPage, pageSize));
            this.gridApi.core.on.filterChanged(this.$scope, () => {

                if (this.filterTimeout != undefined) {
                    this.$timeout.cancel(this.filterTimeout);
                }

                this.filterTimeout = this.$timeout(() => this.filterRequests(), 500);
            });
        },

I've set debuggers inside the filter methods but it doesn't get triggered by pressing enter only when you type a character.

Does anyone know what is triggering this button when enter is pressed?

UPDATE 1

    <button class="btn btn-primary" ng-click="vm.open()" translate="country.headers.selectCountry"></button>

    <div id="grid1" ui-grid="vm.gridOptions" ui-grid-pagination></div>

    open() {
        let instance = this.$uibModal.open({
            templateUrl: 'app/common/controllers/html.html',
            controller: 'controller as vm',
            backdrop: 'static',
            windowClass: 'country-modal',
            resolve: {
                programId: () => this.$stateParams['programId']
            }
        });
        instance.result.then((dataGenerated: boolean) => {
            if (dataGenerated) {
                this.loadData();
            }

        });
    }

UPDATE 2:

private filterRequests(): void {
        let grid = this.gridApi.grid;
        this.filtering = [];

        for (let i = 0; i < grid.columns.length; i++) {
            let column = grid.columns[i];

            if (column.filters.length > 0) {

                for (let j = 0; j < column.filters.length; j++) {
                    let filter = column.filters[j].term;

                    if (filter != undefined && filter != '')
                        this.filtering.push(column.field + '.contains("' + filter + '")');
                }
            }
        }

        this.loadRequests();
    }

loadRequests(): void {
        this.service
            .get(
            this.model.id,
            {
                params: {
                    page: this.pagingInfo.page,
                    pageSize: this.pagingInfo.pageSize,
                    sort: this.sorting,
                    filter: this.filtering
                }
            })
            .then((data: any) => {
                this.gridOptions.data = data.data;
                this.gridHeight = (this.gridOptions.data.length + 2) * this.gridOptions.rowHeight;
                this.pagingInfo.page = data.page;
                this.pagingInfo.pageSize = data.pageSize;
                this.pagingInfo.totalCount = data.totalCount;
            });
    }

With kinds regards, Brent