Latte-Dock does not always respect the Opacity Settings. At the moment I have Latte Dock as a "Dock" at the bottom of my screen, with Opacity set to 25%. Regardless of if Shadows are enabled or it is set to Solid. I'm unsure what information you require, so please let me know an I will attach it as soon as possible.
After some additional testing, It seems that this only occurs if Latte-Dock is set to "Panel". Setting it to "Dock" allows transparency to work.
Probably some screenshots showing the issue and the settings in Appearance to understand what is the issue
I need steps to reproduce... first step could be to add a new dock with default settings...
*** This bug has been marked as a duplicate of bug 397431 ***