I'm trying to produce a custom sized PDF (841 x 3567mm). The preview in QGIS composer looks fine but when the Export to PDF is completed I'm missing the bottom portion of the PDF image. The composition is comprised of vector and raster layers (ECW) and some of the vector have a transparency setting. I've trying turning off the transparency to see if it is having an affect but still getting the same output, so it doesn't seem to be related. See image attached.
This is a know issue coming from Qt. Since exporting relies on a single QPainterthe requested export can hit the limitation ( https://doc.qt.io/qt-6/qpainter.html#limitations ). The solution may be to lower the resolution or fix/fund a fix to stich images when it exeeds the size limitation of QPainter.