I haven't been able to find a proper report for this bug in here, so I'll post one.
Sometimes, when I open the game, all the stats on my weapons are "nerfed" (that is, reduced). This is what it looks like:
Usually, a game refresh is all it takes to bring things back to normal. These stat changes are effective (that is, the stats are effectively reduced and it's not just a display error). it also affects passive gear, crafted clothing, and items shown in chat. It does not affect non-crafted clothing as far as I know, but I wasn't able to confirm if it affects books, components or active gear.
At the same time, I got the following error when I tried to hover my mouse over a Crafting Kit to see its description (the description window did not appear):
TypeError: Error #1009: Cannot access a property or method of a null object reference.
This error only applied to Crafting Kits and not on weapons, gear or clothings (I couldn't test it in other items).