Worksession window super slow with large pointcloud files attached

I have 2 ~1GB pointclouds attached to the model. It takes the same amount of time to open Worksession window to save 5KB rws file as to load/attach both pointclouds again (meaning: it seems that Worksession command loads pointclouds again). Why?

The pointclouds are on the network drive if that matters.