Windows 10, 64 bit, GeForce GTX 1060
Blender 2.80 (sub 35), branch: blender2.8, hash: 74db65e5424
Short description of error
This bug was in 2.79 and was fixed, but it seems that is in 2.8 Beta too .
Unwrap Error StarTestBlender28.blend show how bad it is.
Exact steps for others to reproduce the error
To reproduce this, just select all faces in the image then do an Unwrap ( any setting it's the same ). It's the same bug like in 2.79 that was fixed in there, but in 2.8 Beta wasn't fixed .