Hi,
Going back to v53, I get mode 2 behaviour (transparency is transparent, text is white), with or without the mipmaps toggle on.
Some more observations having gone back to v56.
Displayed 3D windows can switch from one failure mode to another. Windows start in mode 2 or mode 3 (though I mostly have only seen mode 3 on startup with the TE Federation non-compact HUD; changing to compact usually guarantees a mode 2 start).
Failure mode can spontaneously change; often this occurs when the window gets refreshed, and in particular it can occur when another 3D window for the same avatar is updated.
I'm going to send two screenshots via email. One is TE, showing the white text and correct transparency. The other is TE3K which started the same but changed to mode 1 while I was clicking in TE (ie TE3K rendering changed during interaction with TE window). This is what I'm calling mode 1 where transparency hasn't rendered transparent but the text is now the right colours.
regards
Chorazin