I've found a bug in bloom event: it doesn't always autosell the lowest flower. I had 10-5-4-3-1-0 + 1 empty slot, and after breeding (flower L7 with splitting gene) I got 10-4-3-1-0-6-6.
UPD: from my observations, it removes lvl just below one it tries to add first and then searches down to lvl 1. Probably invalid search loop direction...