Season summer, cacti obviously in bloom, but when picked, only dropped cactus flesh, no flowers. I had two mods enabled when I generated the world, so it seems likely it was a mod bug, except they were only interface mods (map and status) so how could that affect gameplay? On the other hand I was crashing when I tried to pick the cactus (and a lureplant) until I disabled the mods. I leave this here for completeness sake, if others without mods start reporting cactus issues then you know it's the game, otherwise let's put it down to modding issues!
Steps to Reproduce
Summer; picking cactus plants.
This issue has not been confirmed by a developer yet.