This bug happens on baby nero, I am not sure if it happens to any pet. When you reselect the boss pet and then CC, the previous pet(s) who were a boss pet before will unsummon. See video below for example
https://royals.ms/forum/threads/clarifications-regarding-multiple-pets.146533/#post-865596 Basically if you want to change boss pet, unsummon all of them , then summon them back, summon the new boss pet you want first. Since you have all 3 of the same, just click 'Cancel' when that screen of changing lead pet appears
Ah okay thank you. Can close this thread then since I think this is a known issue to staff, judging by the post you linked
Will be closing this thread This bug is indeed known to Staff and some players Unfortunately, it's a tricky bug and the Staff are unable to fix it currently, can only offer the advice of canceling 'Lead Pet' for now Thank you for your understanding about the bug