Going trough a portal can destroy shulkers

i was helping a friend setup her nether portal on the roof and she send me the cords to her base. i devided that by 8 and then build a portal there on the roof. when i went in the portal it spawned a new portal in the middle of a shulker monster, meaning it took out 4 shulkers which could have been full of materials to build with or valuebles. i understand that a portal spawning could replace blocks sometimes but i think having it replace shulker boxes should not be possible

How to reproduce:
step 1. have some shulkers next to each other (aka a "shulker monster")
step 2. devide the cords of the middle with 0
step 3. build a portal there in the nether
step 4. if there isnt a portal near that place. it is likley to spawn a portal in the shulkers and replace some of them
i includes the picture of the accident