Got all sites updated to 4.2.8. No issues, SPPB 3 works fine as before. It's was only a security update, no other files are updated.

Ya, not my experience.

Hi,

I have few private sites on SPPB 3.8 + Joomla 4.28 and so far no problems with Page Builder. Only new Joomla makes problems from time to time, like alwys with new versions.

Yes, it's fully compatibile. Besides, component code is this same.

1. Do you use front-end or back-end editor?
2. What Joomla version you had before "problems times" ?

1. I made simple test, created a new page "test 123" with random addons , rows - no problems, all smooth as always.

2. But indeed module "Topbar Right Heading" is now empty. In "Topbar Right Heading (copy)" I imported you orginal content of that module, so you can work on that.

without video with issue details - hard to guess what is wrong ....