Gutenberg custom block: RichText underline button

In a block that I am currently trying to build I am using a RichText control.

This has buttons/menu items for Bold, Italic, Code, Link, Inline Image and Strike though.

Though there isn’t a button for underlining the text I can just use the key command [cmd+U] and it underlines.

This seems to work and is saved on the frontend and backend.

If it was working. There could be a few issues why it has stopped. Have you any errors in the console?

Have you tried removing the block and re-adding it?

EDIT: I am a beginner with Gutenberg block development so I am out of my depth!

You might find this useful if you haven’t already come across it.

Add Formatting Buttons to Gutenberg core/paragraph BlockControls