How many times were you able to reproduce it?

Always

Steps to reproduce

1. Open https://test.wikipedia.org/wiki/Maths (or any test article with wikitext similar to <math>k(\varphi)=4(\cos\varphi,\sin\varphi) \ .</math>)
2. Edit the article by making a change to something other than the math section
3. View the resulting edit

Expected results

Math syntax remains as <math>k(\varphi)=4(\cos\varphi,\sin\varphi) \ .</math>

Actual results

Math syntax is converted to <math>k(�arphi)=4(cos�arphi,sin�arphi) .</math>

Screenshots

Environments observed

App version: 6.2.0
OS versions: Any
Device model: Any
Device language: Any

Affected articles?

• https://test.wikipedia.org/wiki/Maths

Original report

In this edit https://en.wikipedia.org/w/index.php?title=Nephroid&diff=888397681&oldid=867946367&diffmode=source the user is attempting to fix a link, but it also corrupts much of the mathematics

Changing
<math>k(\varphi)=4(\cos\varphi,\sin\varphi) \ .</math>
to
<math>k(�arphi)=4(cos�arphi,sin�arphi) .</math>

I suspect it was not the users intention and looks like a character encoding problem.

The edit was tagged with Mobile edit, Mobile app edit, iOS app edit

I can't verify this as I don't have an iOS phone.