Why doesn't the delete key delete characters?

In Windows 10, LibreOffice Writer, pressing the Delete key (Del) doesn’t delete characters to the right of the cursor. Why and how do I fix it?

Buy a new keyboard, maybe?

That’s difficult to accomplish with a laptop, and besides, there’s nothing wrong with the keyboard. The Del key works as expected in other programs. This is specific to LibreOffice.

It’s not happening only in Windows 10. Also in Lubuntu 20.04 with LibO version: 6.4.5.2
Build ID: 1:6.4.5-0ubuntu0.20.04.1
CPU threads: 16; OS: Linux 5.4; UI render: default; VCL: gtk3;
Locale: es-MX (en_US.UTF-8); UI-Language: en-US
Calc: threaded

I checked the shortcuts dialog and no command is associated. As reference, backspace key is associated with Backspace function. Is this part of the problem? There are many Delete something commands, and none of them is the regular Delete-character-right-of-cursor function.

Also, this bad behavior started when upgrading to this specific branch of LibO: 6.4.5.