The last knot on my Talis always opens up which causes the shamash to unwind. I applied some glue to the knot to keep it in place so that it wont open. Is this a problem? The glue also went on the shamash & some of the tiztiz. I know that Dayan Fisher allows one to place glue on the tip of Lulav so I thought this would be OK as well.
Without connecting the sugya to the Lulav issue, this is fine.
The purpose of a knot is that the stings will not untie. If glue aids a knot in so doing, there is no problem in this.