I just upgraded from QGIS 2.18 to the latest stable release (3.4.5).
I am trying to filter an attribute table added to a layout by using @atlas_pagename and I can see there is a match in the expression builder but my table stays blank as if it can't find a match.
This might be the same issue as in this thread (the same problem in 3.4.4) : QGIS 3.4.4 Attribute table expression not working anymore but on the bug tracker this issue has been closed and reportedly it was solved and corrected for the next release.
Can anyone confirm it's still broken in 3.4.5? I don't know how to report/reopen bugs but will happily report it if anyone can tell me how.