When I opened the Steam overlay during match finding, the characters started stacking infinitely. This caused for significant lag. When you close the Steam overlay, the extra models disappear.
During the queue time, the background turns misty green and a standstill of a hero appears, watch and observe
After the first hero fades out, the second hero fades in and will be clipping through the first
This repeats ad-nauseum, all heroes stacking on each other. Unsure if possible for heroes to duplicate and stack infinitely one all have been cycled through,
Workaround
Exiting the steam overlay removes the issue, only one hero appears on screen and heroes do not stack after the current one fades away.