NotJustBikes made a video about the highest point 'in the Netherlands', that's where I heard of it.

It is correct though, since 2010 Saba is a "speciale gemeente" of the Netherlands, and its mountain is thus our highest point. Before that it was organised as a separate country "Nederlandse Antillen" with the other Caribbean islands.

The Netherlands highest point is in the Caribbean though

https://youtu.be/UJkVHgFsF60