Van Hooydonck first time loss was in the Vingegaard mechanical debacle.
Then he was in the group with Vingegaard and Van Aert through the Roglic crash site.
Then he waited for Roglic around the time when there is a second time loss (27 km to go)
Or IOW, for the graph to work, it should be marked when Van Aert joined Vingegaard and Van Hooydonck joined Roglic
What you said is correct. This graph is misleading unless you look at it well and use the footage next to it. When van Hooydonck joined up with Roglic he was a minute behind the Vingegaard group.