This is an outdated info from 2021.
There are no voyages between April 12 and April 29, 2023.
Voyage H308N ends in Vancouver, BC on April 12,
Voyage H310N starts in Vancouver, BC April 29.
So most likely, dry dock will be in Victoria, BC. Although Portland, OR would be possible, too.
The last scheduled dry dock was from December 31, 2020 to January 17, 2021 in Portland OR.
As the two years are over, it looks this will be just a routine dry dock with the usual refurbishments.