blotchy glossy glass

[shaggray]

i am rendering frosted glass and it`s got strange blotches


my settings are:

glossy: 0.7
subdivs: 10
IOR: 1.0
maxdepth 1


AA: adaptive subdivision -1/2

i am rendering from an irradiance map where the glass was hidden.
could this be the problem?

[natty]

yeah that is probably the problem.