This might be a stretch, but wonder if these have anything to do with it…they were installed on the southwest end of that triangulation, no?
https://www.zerohedge.com/news/2018-10-22/canada-installs-underwater-chinese-monitoring-devices-near-us-sub-base
https://www.scmp.com/news/china/society/article/2169474/canada-installs-chinese-underwater-monitoring-devices-next-us