I am having a problem with the plastic edging. Mainly it occurs where pavers meet beds. Where turf comes right up to pavers the edging is fine. but in beds it seems to expand, warp and rise up. Pavers are installed correctly in base and sand etc etc. Edging is installed per manufacturers directions. It is at the bottom half of the pavers and I have nailed it with spacing from 15" down to 3-4" in experimenting to solve the problem. Seems to be more of a problem on straight runs. I have tried relaying edging on hot sunny days after it sits in the sun thinking it would shrink but it still seems to work free. Any ideas or alternatives?