I and many others who I've interacted with have noticed an issue in desktop mode when using a world that makes heavy use of UI "inputfields". (Karaoke central being a common example)

At seemingly random, keyboard inputs meant for movement suddenly start typing into inputfields. VRChat has long since moved past this style of typing into inputfields, (it now brings up a keyboard menu specific to input fields.) Despite this, when walking around normally or crouching or jumping, Characters get typed into the inputfield.

After finally trying to find out what causes this in game, I found that clicking down(hold) on nearby UI elements, and moving your cursor, before using a keyboard input seem to cause the UI input to start accepting keyboard input without the keyboard popup.

I'm unable to find any more specific details on requirements to cause this bug. UI inputfield existing, and clicking and dragging on any other UI in the map.