Hello. Sorry for posting in English. It appears that the hierarchy of urban streets in Heraklion was downgraded to tertiary and lower over a month ago. The old hierarchy is still visible on maps that take longer to update, like osm.de (although note the different palette; for example, secondary highways are orange on osm.de and yellow on osm.org). Not sure if this is an experiment or if it was agreed upon, so please have a look. The urban highway class distribution now looks very low compared to Athens, Chania and cities of similar size and structure, and competing commercial maps.
Edit: capture from osm.de for reference in case it updates in the meantime