[How it happened : ]
After navigating through crafting screen, I came back on the inventory to find giant letters written in white on the screen. So far I had two "W" and now the letter "A".
[Comments : ]
I could reproduce the bug only once so far, I tried navigating through the potions to craft, without crafting any, and the bug occured. I only have one screenshot.
You can see the letter A just beneath the character portrait on the screenshot.
[Attached files : ]
Screenshot linked