playback speed not working and using the default youtube speed step

1. Bug Report:

⚬ BUG:
⚬ Browser:
⚬ HOW:
⚬ Does the bug not happen when you log out of YouTube? Or did YouTube change at all? - Then please check your 800+ experiment flags list with and without the error: Enter: yt.config_.EXPERIMENT_FLAGS into the Browser console on youtube (F12-Key). (Messy alternative: Copy the html-source you get with ctrl+U.)
⚬ Or did our last update start the bug?
⚬ Are any *Browser console errors shown? F12-key
⚬ ImprovedTube Version:

⚬ *Screenshots*:

                                 ⚬ *Expected /preferred behavior*: 
                                 ⚬ *Context*:   

Step-0 / Before submitting

Thanks for coming & caring! Please check if the issue has already been reported ever. ( With GitHub's issue search (use this link)
(else removing "is:issue is:open" from the standard search)

More:

⚬ Tested alone without other YouTube extensions or in incognito mode? Yes/No
⚬ My Settings:

List your settings or export them to paste or attach</summary

⚬ DOM:

maybe attach or paste collapsed

(here)

(How-To: https://github.com/code-charity/youtube/wiki/Contributing#Test )
⚬ OS:
⚬ Device:

No source file, test, browser, version, reproduction steps, or expected behavior are provided. Start by reproducing the playback-speed problem on YouTube and determine where the extension applies its speed setting versus YouTube's default speed step; done means the configured playback speed works reliably.