The accident was during lifting tests.
A loaded barge is alongside Orion under the crane, probably the test weight. In the first video, she is strongly moving up and down.
Five injured in the crane cabin.
Tech infos about the Liebherr crane (the first of this kind):
https://www.liebherr.com/en/che/products/maritime-cranes/offshore-cranes/heavy-lift-crane/heavy-lift-crane.html#!/accordion-start-module-1=foldable-a-frame+accordion-item-start-module-3+accordion-item-start-module-2
The vessel Orion (still propriety of the yard COSCO as Orion1):
https://deme-group.com/technologies/orion