Thank you for your post.
I was unable to reproduce the issue in a new file hosted on FileMaker Server 14.0.4a. To attempt to reproduce I followed these steps:
1. Created "Test.fmp12"
2. Created Popover Button on the far left of the layout, set it to pop to the right
3. Setup for WebDirect
4. Uploaded to FileMaker Server
5. Accessed via WebDirect and tested in Safari, Google Chrome, and Internet Explorer with no additional flashing or "buggy" behavior
Are you able to cause the issue in a new file or do you have further information needed to reproduce?
Reset the popovers to open to the right today and everything worked perfectly. Can't explain the difference. Two of us were working on the issue yesterday for 1/2 hour. Whatever . . . as long as it's working.