App crashes when BLE write calls a lvgl screen to show

Question

My app keep crashing when I call a screen change from a bluetooth write function. The central sends a message to the peripheral. The peripheral wakes up the display and tries to show a lvgl screen with a single label. I see it for a second. I keep thinking I need a message queue or a different thread for the display. I can try a few things but didn't want to guess. 
 This is the write callback on the peripheral: 
 static ssize_t write_vnd(struct bt_conn *conn, const struct bt_gatt_attr *attr,
 const void *buf, uint16_t len, uint16_t offset,
 uint8_t flags)
{
	//this means a write has happened to the peripheral, the controller has written
	uint8_t *value = attr->user_data;

if (offset + len > VND_MAX_LEN) {
 return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
	}

memcpy(value + offset, buf, len);
	value[offset + len] = 0;

screenmanager_show_token();
	eventhandler_reset();
	return len;
} 
 
 it calls the: void screenmanager_show_token() {
 //clear the current screen and show the next
 lv_obj_clean(lv_scr_act());
 screen_token_init();
} 
 
 which is just: void screen_token_init() {

lv_obj_t *token_label;
	token_label = lv_label_create(lv_scr_act());
	lv_label_set_text(token_label, "Hello World");
	lv_obj_align(token_label, LV_ALIGN_TOP_MID, 0, 0);

}