Since 2018 I've been noticing that pets can block your character from walking or even pick up items properly because by bumping into the pet you are "pushed back" back to the place of origin.
Summing up: It's like a Macro / Botter trying to kill bixos behind a tree.
Where in our case Pet would be the tree!
Ps: It is possible to even block the portal (skill) just by leaving the pet on top of it.
Is super annoying that bug in some cases.