That’s because Obsidian assumes you are trying to mix HTML code with Markdown code (<foo> is considered an open HTML tag and must be closed with a corresponding </foo> tag, same for <bar> that requires a </bar>, in which case the image will show up just fine)
Solution: to avoid this, you must escape any HTML tag with a \ prefix, like so: \<foo>-\<bar>; this will tell Obsidian that you are NOT trying to mix HTML with markdown code, and that you actually want the angled bracket (even this forum will not allow you to type <foo>-<bar> without escaping the open-angled bracket)
So no, this is not a bug, this is just a consequence or side effect of Obsidian users being allowed to use both HTML and markdown code inside a note. This happens in other markdown apps as well, not just Obsidian.