BooleanUnion incorrect union

Rhino
1

What are the reasons that after doing BooleanUnion there appears holes?
Reference below.

Ekrano kopija (112)
Ekrano kopija (112)1920×1080 231 KB

Ekrano kopija (113)
Ekrano kopija (113)1920×1080 228 KB

2

Hello- if those are all coplanar surfaces, use PlanarUnion

-Pascal

3

Thanks, Pascal