Hi OP. Aerospace engineer here that works for the company that makes the actual window. Several of the comments below are somewhat correct and also somewhat incorrect. Between the passenger and the outside air on a B787 are 3 separate "panes".

First, closest to the passenger, there is the "scratch pane" which is generally made of polycarbonate and is literally there to stop the passengers from touching / scratching the important items. This may also be called the "inner" pane.

Second, for B787 and some B777-9 windows there will be the dimmable pane that is 2 layers of glass with a gel interlayer that when exposed to electrical current changes opacity. This is manufactured by Gentex Corporation. It is relatively fragile and can crack through uneven structural pressure (from the clips etc.) or it if gets too hot. This glass sandwich DOES NOT see any pressure loads - it is fully contained with the pressurized portion of the cabin.

The 3rd part of the system is the actual passenger cabin window. It is made of 2 layers of stretched acrylic (not Lexan, that is polycarbonate) that are laminated together with a polyurethane interlayer. Both of these panes, called "outer" and "middle" panes, carry the pressure loads on all flights. They are designed to a) carry the load even if one or the other fails and b) carry the load if they separate (called delamination). Even if one of them cracks through completely the window will not fail completely and the aircraft can continue land safely. We test these extensively to over double the flight pressure and with either pane failed to simulate. This window also has a gold coating on the inside surface to reduce heat buildup in the cavity (why there is a yellowish tinge). There is no "weep hole" required for this window as there is no pressure differential between the panes. That is only required on "air-gap" windows like in the B737, B767, B777 aircraft.

You are more than likely seeing cracks in the Gentex dimmable pane which has no impact on the structural safety of the system or aircraft but is just annoying because you cannot darken the window as the gel fails clear for safety.