diff --git a/app/src/plugins/tm@modal/task/z-task-modal.vue b/app/src/plugins/tm@modal/task/z-task-modal.vue
index 454a157..c7d3f3c 100644
--- a/app/src/plugins/tm@modal/task/z-task-modal.vue
+++ b/app/src/plugins/tm@modal/task/z-task-modal.vue
@@ -277,6 +277,7 @@ export default {
 
 		showCompleteTaskModal() {
 			this.$events.emit('show-complete-task-modal', { subtask: this.subtask })
+			if(this.subtask.deadline) this.subtask.deadline = tmUtils.formatDateTimeForBackend(this.subtask.deadline)
 		},
 
 		filesUploaded(files) {