I reproduced it like this:

1. Open the app.
2. Find the article "ASCII".
3. Tap the pencil, and edit the article.
4. Highlight some text. A panel appears with COPY, SHARE, EDIT HERE, SELECT ALL. (This is already weird, because I don't expect "Edit here" to be available here.)
5. Tap COPY. Nothing happens.
6. Open you SMS messages app. Long-tap and press Paste. The text that you selected in the Wikipedia is not pasted.

This was reported by a Hebrew Wikipedia editor, and I could reproduce it in both Hebrew and English.