Why does new junk mail automatically get marked as read?
Good question – one can easily miss new messages which have been incorrectly marked as junk. Workaround: Both for trash and the junk folder, one can enable displaying the number of ALL messages in the preview pane (in brackets after the folder name) by using the environment variable EVOLUTION_COUNT_TRASH=1. Note that versions 2.26.2 and later of Evolution no longer mark Junk messages as Read.