In my WebDirect solution I wanted to extend my own menue which was build with a button bar.
The segments should have alignment left.
After I have add a second line the rendering in WebDirect was wrong - in a FileMaker client it was like I have styled.
So I worked out a little template and also noticed that the wrong rendering only applies if the button bar has a saved style. If the alignment is a local style attribute, the WebDirect rendering is fine.
FileMaker Server-Version: 220.127.116.11 (Windows Server 2012 R2)
Tested on Safari 12.0.3 (macOS 10.14.3)