Text { } not reacting to changes to property 'textFormat' as expected

I've started to use the Markdown for Text {} feature in Qt 5.14.
While it does work very well when initially setting Text.textFormat to Text.MarkdownText, its reaction to changes to that property apears to be incomplete.

I have attached a fully working demo and an image illustrating the issue.

Upon starting the demo, the Markdown is rendered properly, i.e. with bold and italic font and the line break is ignored. When unticking the checkbox, it is set to plain text which is also working properly.
However when ticking the checkbox again, the line breaks are ignored again (as expected in Markdown), but the font is not rendered in bold or italic.

I've also tried forceLayout() to no avail.

I could not find the documentation mentioning any limitation in this regard. Is there anything I have to do or have I simply run into a bug here?