Sitemap XMl works for 4 of 6 context, empty [[+url]] for two context

[DESIGNfromWITHIN]

I have a strange issue, for a client site I use SEO Tab for a long time now, they just let me know that the sitemap is broken for 2 of the 6 sites (each a context)

Have this call:
[[!StercSeoSiteMap]]

Works:

• https://doublertrading.com/sitemap-xml.xml
• https://doublertrading.de/sitemap-xml.xml
• https://doublerparts.de/sitemap-xml.xml
• https://doublerparts.nl/sitemap-xml.xml

Doesnt work, empty [[+url]] the other data is shown!

• https://doublertrading.nl/sitemap-xml.xml
• https://doublerparts.com/sitemap-xml.xml

Nothing in logs, using latest version.
All in the same MODX installation, I have no idea why this doesnt wormk.