Changing display language in Windows 10 does not work correctly (breaks suggested menu items)

Question

Reproduce:

Initially, I installed a German (de_DE) version of Windows 10.

For those who don't want to read or don't understand what I mean watch a video of what I did and what the result was: https://youtu.be/6gjkpGUHehc

Then, I wanted to switch to english,

• so I went to the "Einstellungen" (german for "Settings").
• Then the control panel opened up
• I clicked on "Zeit und Sprache" ("Time and language").
• Then "Region und Sprache" ("Region and language").
• Then "Sprache hinzufügen" ("add language").
• Added English (United States), set it as default.
• Removed German.
• Went to options for English.
• Installed the three items that were available for download.
• Added German keyboard.
• Removed english keyboard.
• Waited for installation to finish.
• Went to the link "Zusätzliche Datums-, Uhrzeit- und Ländereinstellungen" ("Additional date, time and country settings". Control Panel opens up.
• Go to "Sprache" (Language) -> "Erweiterte Einstellungen" ("additional settings") set english for first dropdown to make sure it is always used as display language.
• Choose english with german keyboard for 2nd dropdown.
• Click link "Spracheinstellungen für Wilkommensseite, Systemkonten und neue Benutzerkonten übernehmen" ("apply language settings for welcome screen, system accounts and new user accounts").
• Click the button "Einstellungen kopieren" ("copy settings") in the popup window.
• Check the two checkboxes and click ok.
• Reboot.

After reboot, it looks like the system is in english now. However, if I press the Windows key and enter a search term like "program" (because I want to go to the "Programs and Features" settings item in Control Panel, still the German suggestions show up (Like "Programme und Features"). These entries do no action when clicked.
"Anzeige" (english: "Display") has the same issue and so have many other items. However, "Standardprogramme" ("default programs") which appears also when entering "program", works.

Expected behaviour: After reboot, everything is in English, also the suggestions. Also, all items should do the action they are destined for. This was not the case. I tried this also on a fresh installation of Windows with all updates on a different PC.

Does anyone know

1. Why it's not working?
2. How to solve this?
3. Whether Microsoft knows about that issue?