Seger van Groesbeek, /!\

source: Ons Voorgeslacht 1988, p. 85 (Dutch genealogical publication)

kind USER Private User this new date <1382 create temporal conflict
are you sure that the source you cited speaks of him, there, and with that date!?
because now studying the marriage, not even that matches /!\
in the sense you posted the source to confirm the data and relations?
or did you just insert the chapter that talks about the family?

 --> reinported again, again from online suggestion :))  

/!\ -https://gw.geneanet.org/petermkuiper?lang=nl&pz=x&nz=x&ocz=1&p=joha... (1385-...)
sources: Gedcoms, Smart Matching, Genealnets (in the Middle Ages = trash)

on https://www.genealogieonline.nl/west-europese-adel/I88568.php :

• NOT known son of Johan III, heer van Groesbeek en Heumen
• NOT the father of Johan van Groesbeek [moved]
• NOT known husband of Barones Johanna van Isendoorn [conflicting dates]

From 2018 this had also been renumbered & dated as DUP of his grandfather:
Seger II, heer van Groesbeek en Loenen (1340-1405) in "smart mach" too
so maybe can he actually be his grandfather's DUP?