Every piece of glass has some streaks, just some worse than others. If you put clear over dark veneers, every little imperfection will show. To me, it still better than colored glass and this too has steaks.
The streaks don't affect strength. They are caused by some fibers taking a little more or less resin during the glass building process. Gordon's is our only hope and most of the glass isn't all that bad, but it is there.
If it was known how much gets culled by them before it actually gets sent out, most would be surprised. If the lines get worse over time, it is actually a different problem all together.
BigJim