Inline keyboard is not removed after being reset by bot

[Danstiv]

Telegram bots have the ability to completely remove inline keyboard, in which case it should disappear in the Telegram client.
Previously, the keyboard disappeared correctly in WebA, but this behavior changed a few versions ago.

Steps to reproduce

1. Open chat with this bot.
2. Press start button or send "/start".
3. Press "Reset" button on the inline keyboard.

Expected behavior

Inline keyboard should disappear.

Actual behavior

Inline keyboard does not disappear.

The keyboard disappears only after reloading the page with some delay (about 200 milliseconds).

Notes

The bot mentioned above was written by me and hosted on my server, I hope it will work when someone starts testing the described problem.
Bot source code just in case.
Correctness of removing the keyboard can be observed in another client, for example the official telegram for android.
There was no problem in some of the previous version, I can try to bisect if necessary.