It looks like it would inhibit cooling the tubes. Is it manufactured or home made? Any chance you can put something like metal screws to 'pin' the reflector up? What about a couple of small blocks or spacers to help push the reflector off the tubes?
If it was manufacturered I'd call them and ask what's up. If its homemade I'd find some spacers to hold the reflector away from the tubes so air can circulate.