Shortcode parsing issue

Hello, it seems every shortcode I write around expressions containing the symbols
“<” and/or “>” are not parsed correctly. In the link I have the following code

[expand title="Proof"]   $ \epsilon_1 ttt   \epsilon_2$.[/expand]

[expand title="Proof"]   $ \epsilon_1 <  \epsilon_2$.[/expand]

[expand title="Proof"]   $ \epsilon_1 ttt   \epsilon_2$.[/expand]

using the collapse-o-matic plugin, but I have the same issue with every plugin I have installed so far, even without the matjax $…$. The first line is parsed correctly, while the second is not, and the third, which is a copy of the first, is also not parsed correctly. The issue persists across themes twenty-fifteen – sixteen and – seventeen which came with my wordpress install, and across multiple browsers (Firefox and Chrome).
I’m completely out of workarounds here, so I’m happy for any suggestions.

• This topic was modified 6 years, 6 months ago by bug9324.
• This topic was modified 6 years, 6 months ago by bug9324.
• This topic was modified 6 years, 6 months ago by Steven Stern (sterndata).
• This topic was modified 6 years, 6 months ago by Steven Stern (sterndata).

The page I need help with: [log in to see the link]