Hi,
thanks for the notice.
So the short answer is no it shouldn’t be listed as a regression bug as you might have seen in error box like in https://www.xwiki.org/xwiki/bin/view/ReleaseNotes/Data/XWiki/14.4/. The reason is that the bug in Loading... concerns the new feature introduced in 14.5 and mentioned there: https://www.xwiki.org/xwiki/bin/view/ReleaseNotes/Data/XWiki/14.5#HDocker-basedMulti-pagePDFExport. So basically it’s not a regression since it just didn’t exist before.
Now maybe the jira ticket title might be rephrased since we might think it concerns the old PDF export feature.