brushwood....I say "just one of those bee things". I did a perfect cut out, caged the queen, and all the bees marched right in.....textbook!!! Until they decided a palm tree in a parking lot was a better location.
They absconded, leaving the queen behind. Same deal with a swarm removal...had the queen, excluder was on the bottom board, everything was great, until they decided to leave, and again, left the queen behind.
I am afraid bees are bees! Hopefully they will find your swarm trap to be their desired location!! It wasn't the queen excluder...they'll leave without her if they choose to! Best of luck!