Expected behavior

Show outline button on a group of radios like here: https://getbootstrap.com/docs/5.1/components/button-group/#checkbox-and-radio-button-groupsOnclick the selected one should get filled as in the bootstrap docs.

Actual behavior

In mdbootstrap same snippet shows the outline button but when pressed has no effect, remains outlined.

Resources (screenshots, code snippets etc.)

https://getbootstrap.com/docs/5.1/components/button-group/#checkbox-and-radio-button-groupsHere's the snippet

Radio 1 Radio 2 Radio 3