Since launch, the PSVITA version's bright green Level Number stays opaque and bright even if you set the Interface Opacity to a low value like 20%. On the PS3 and PS4 versions which I also have, the Interface Opacity also makes the level number fade away.
During the recent patch, another visual oddity is introduced. The Tooltip Text and Tooltip Buttons are fully solid and not see through. Before, Interface Opacity setting can change the transparency of the tooltip buttons and text. While turning off tooltips is a temporary solution, it's not a good option for those people who like or need tooltips.
I think that fully translucent UI especially in a small screen like the Vita is important since there's not much screen real estate compared to a PC monitor or an HDTV.
Another importance of translucent UI is to avoid "Burn In" on the original Vita's OLED screen. Solid static shapes on an OLED screen can accelerate wear of the screen since wear is put unevenly. This is important for a game where you will put hours and hours into.
I have provided screenshots of the visual bugs in question. Hope this is fixed soon!