I don't think there are two respected secondary sources proving Katherine died 5 Nov1387.
Online sites guesstimate several different years for her death, so I don't think we know when she died. I may be wrong.
Online websites of vapid value guesstimate several years for her death, including: https://www.findagrave.com/memorial/109883008/catherine-de_grene
Wikitree nonsensically shows her death on 5 Nov 1370—in Broughton, DORSET, England—but provides no source: https://www.wikitree.com/wiki/Greene-2059
