We contacted LP Aero plastics regarding the crazing on our RV10 windshield. They said the cause was the use of automobile reflective inserts on the inside of the plexiglass. They said there is a chemical reaction from the materials in the sunshields that causes the crazing.
Even Bruce's custom cover's does not recommend the use of their internal sun shields for more than a couple of hours at a time..."We would only recommend using sun shields 'HeatShields' for temporary use during day trips or for a couple of hours at a time during a short layover. If used too frequently over time, the silver reflective surface can cause damage to your Plexiglas windscreen and laminated windshields as it traps heat in between your glass and the HeatShield."