sitemap.xml + WPML results wrong “alternate”

There is a problem with generated “alternate” link in sitemap.xml when using WMPL.
4.0.15 update did not resolve this problem.

Imagine I have a page (original EN language):
https://website.com/Hello-World/
and translated German version of this page:
https://website.com/de/Hallo-Welt/

BUT in sitemap.xml I see:

<loc language="en"><![CDATA[https://website.com/Hello-World/]]></loc>
<xhtml:link rel="alternate" hreflang="de" href="https://website.com/de/Hello-World" />

It just adds/changes language prefix but not a link itself.
(“Hello-World” is not changes to “Hallo-Welt”)
I tried dynamic sitemap, static sitemap and all available options in plugin settings. The problem is still there.

Please make update to resolve this problem.

Much thanks in advance.