Cool white are a brighter bulb so if you used all those perhaps that is accounting for some reflection .You can definitely use a lot less LEDs in a backbox than incandescents and get the same brightness. If you packed it full of cool whites it'll definitely glare a bit.
I'd try removing some of the whites if this is the case and tone down the brightness or perhaps throw in some colors you like as they are not too bright.
I would recommend frosted bulbs as well for less glare!