Both the in game and out of game compendiums do this, and I haven't seen it reported anywhere else. My compendium, if I were to use the filters to look for only Creature Rating 1 monsters it would also include all other monsters with the number 1 in, it for example: This happens with other assortment of numbers aswell, CR 2 will give me higher CR creatures aswell as lower ones like 1/2 CR.