My crank arm came off within first 10 miles on new new emtb bike. Need help identifying broken part.

I was riding the other day and out of nowhere my crank arm came flying off. I am looking to reattach it, however it looks like there is a spacer or bushing that broke. The part is not in any of Shimano's diagrams for the crank set up. Would anyone know what part this might be or is this part of the crank arm that became dislodged?

Image link

https://preview.redd.it/new-ebike-crank-arm-came-off-within-first-10-miles-looking-v0-ctz9xca02n2d1.jpeg?width=1080&crop=smart&auto=webp&s=0182942951ea1bb6794b3e31b0859771cb4b7db7

Shimano FC-EM600

https://bike.shimano.com/en-EU/product/component/shimano/FC-EM600.html
Thanks