What is causing these faces to have their UVs flipped?

Here's something that's happening as I adjust the UV offset of some faces:



Note that the upper faces move in the opposite direction as the lower faces.

What causes this? If I select the lower faces and choose "Flip U", then everything lines up perfectly. But those properties are very fragile. (If I later select two faces, one that has Flip U and one that doesn't, Flip U gets unchecked on all faces.) Is there a way to tell ProBuilder not to flip the faces like this, while still using Auto mode?

 

I'll see if I can get this into a test case. If so, I'll submit a ticket and include the bug report URL here.

 

This was actually easy to reproduce. I've submitted bug #1103279 (https://fogbugz.unity3d.com/default.asp?1103279_39p00aoettd6huu1) about this, but here's the short version: Bridge Edges adds faces with a Texture Group of 0, rather than using the Texture Group associated with nearby faces. To reproduce:

Create a new PB cube, and make it tall and wide (drag the top face up about 10 units, and the right face right about 10 units). Add some edges between the faces using the Connect Edges, creating a square in the middle of the face.



Note in in the UV editor that things look fine. Now delete that middle face (backspace with it selected), then select the edges above and below the gap, and choose "Bridge Edges":



Now note that the newly added face is on the opposite side of the UV chart. Adjust the X Offset will move the texture in the opposite direction it normally would. Clicking "Flip U" for this face will put it back where it "belongs" in the UV chart:



HOWEVER, one more issue is that Flip U won't "stick". After clicking Flip U on this face, shift-click any other face, so that the central face and another face are selected. The UI will show that Flip U is no longer even partially checked:



And the UV window is now lying, as it's still showing that central face where is "belongs". But now just adjust the X-offset any amount and the central face will pop back over to the right again:



So, two issues:

• Bridge Edges is adding faces that are U-flipped. This can be corrected later by changing the Texture Group of those faces to match the texture group of its neighbors.
• Selecting a U-Flipped face and then multi-selecting another non-U-Flipped face will clear the U-Flipped flag from the first face.