okay so like me and my friends are at utility i was making a elevator and my friend was like "can i help you?" a'm like "sure!!!" and he/she helped me and for some reason he made a plank and when he/she was going to spawn another plank it got on my elevator that i was making!!! help please and thank you!!!

It sounds like is an old bug, where if two people summon simultaneously they will attach to each other.