Adsense code being corrupted

I run several websites with the same theme and the same plugins. On my site https://www.free-binaural-beats.com for the past few weeks I have not been able to add adsense code without the code being corrupted once I save it. I was not having this issue at all up until a few weeks ago, and this issue is not happening on my other sites i.e. https://www.free-meditation-music.com. Also the code on the site that was there before a few weeks ago is fine unless I try to save it again, then it is corrupted. For example:

https://www.free-binaural-beats.com/downloads/female-health/

This page was created a few months ago and all the adsense ads are running fine. However If i were to update the page itself, the leaderboard ad would get corrupted. If i were to go into the widgets and “save” the text box with the ad it would also get corrupted.

Here is an example of a new page where I tried to add the code to the widget for the sidebar

https://www.free-binaural-beats.com/downloads/528hz-binaural-beat-transformation-miracles-dna-1hr-hq/

The last box in the sidebar is where i tried the adsense code (the other “ads” are images i placed”

Here is the original code i put in.

<script async src=”//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js”></script>
<!– Free Meditation Music Responsive –>
<ins class=”adsbygoogle”
style=”display:block”
data-ad-client=”ca-pub-6577146008166045″
data-ad-slot=”5491616481″
data-ad-format=”auto”></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script>

This code is corrupted to this every time i save whether it is a widget or post

<!– Free Meditation Music Responsive –>
<ins class=”adsbygoogle”></ins>

(adsbygoogle = window.adsbygoogle || []).push({});

Again I am not having this problem any of my other sites that are running the exact same theme and plugins – unfortunately though this is my most popular site so any help would be very much appreciated!

Kind regards.