This is a problem with regular Lemmy web as well. When you select the text and press the button, it inserts the > symbol only once instead of at the start of every line paragraph.

Take this sample text (from here)

Implementations of Markdown are available for over a dozen programming languages; in addition, many applications, platforms and frameworks support Markdown. For example, Markdown plugins exist for every major blogging platform.

While Markdown is a minimal markup language and is read and edited with a normal text editor, there are specially designed editors that preview the files with styles, which are available for all major platforms. 

When I use the quote button:

Implementations of Markdown are available for over a dozen programming languages; in addition, many applications, platforms and frameworks support Markdown. For example, Markdown plugins exist for every major blogging platform.

While Markdown is a minimal markup language and is read and edited with a normal text editor, there are specially designed editors that preview the files with styles, which are available for all major platforms.

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Expected formatting:

Implementations of Markdown are available for over a dozen programming languages; in addition, many applications, platforms and frameworks support Markdown. For example, Markdown plugins exist for every major blogging platform.

While Markdown is a minimal markup language and is read and edited with a normal text editor, there are specially designed editors that preview the files with styles, which are available for all major platforms.