Tell us what you are trying to do?
I have added two sites to the site above for English and German translations. In the documentation it says the should mirror the main (Dutch in this case) site but they completely redirect to it. I have already asked my hosting provider what could be the issue but they told me it's wordpress related.
My first thought would be that my redirection plugin is doing that, but I tested the url's with all plugins off, theme off, database connection broken, .htaccess reset and any information I could find to try.
For now I have set it up as using the parameter for different languages, my client needs the extra languages for their business. I can provide you with login credentials if needed. The secondary domains still redirect to the main site so you can still see the issue.
As far as I can see your site that finishes on .nl points to a different IP address than the .de and .com sites and you are using Cloudflare CDN on your .nl domain.
Also looking at your sites, I can see that there is a 301 redirect - which is a permanent redirect from the .de/.com site.
You should check your Cloudflare DNS settings and adjust them so that they point to the same server and that you don't have any 301 permanent redirects.
To quickly test that the domains are properly configured, you should be able to see the same website (in your case the .nl from both .de and .com domains) when WPML is disabled.
Let me know if those settings are set correctly and if the issue still continues.
After some deeper looking around in the wp-admin I found out the issue was that the subdomains had appointed the main domain as being theirs as well. Likely caused by the switch from dev location to live. Which uses other domains for me.
So the solution was to create a new WP installation, import everything from the other location and redo the WPML setup with the right domains. Bit of work but everything is fixed now.