I upgraded my Magento 2.4.3 to 2.4.4 a couple of months ago, (running on Nexcess - Centos 7, Maria DB 10.5) and went to create some content yesterday. Apparently, it's been some time...
I noticed that PageBuilder wasn't converting my HTML into PageBuilder pages (they were all created in 2.4.3 with PageBuilder). You can see the PageBuilder CSS tags, so the info is there, but they aren't converting to a graphical UID - they come up only in HTML.
Further, when I went to create new PB screens, the Row tool isn't inserting/creating a Row. Columns were, strangely, working. The means I can't design new content.
What am I missing? No new switches to turn PB on, or anything like that... But right now, no real content creation is possible - if I do in HTML, it not only takes forever, but I can't match styles or ensure I don't create errors.
Did you find a solution to this? I have the same issue when upgradring to 2.4.4.
I haven't but an upgrade to 2.4.5 lets me insert Rows again, so I can create new content, but not edit old content except as HTML.
Because I still haven't completed the upgrade fully (I've had issues and had to back it out), I'm still not certain about this, so I'll update this thread when I do (hopefully later this week)....
I also haven't gotten a local dev environment working which would let me poke through the code that executes/is supposed to execute when PB comes up, to determine where the failure is.