Bad encoding of non-English characters

I'm using SalamCast for a couple of months now and everything works fine, excerpt that non-English characters in titles and subtitles are misencoded.

Example feed: https://www.paranormalium.pl/salamcast/rss-encoding-issue.php?aud=48

Have a look at this, it should say 'Mówią Świadkowie', but instead, it says:

<title>M&#195;&#179;wi&#196;&#133; &#197;&#155;wiadkowie</title>
<itunes:title>M&#195;&#179;wi&#196;&#133; &#197;&#155;wiadkowie</itunes:title>
<itunes:subtitle>Wszystkie odcinki audycji M&#195;&#179;wi&#196;&#133; &#197;&#155;wiadkowie</itunes:subtitle>



<image>
<title>Logo M&#195;&#179;wi&#196;&#133; &#197;&#155;wiadkowie</title>
<link>https://www.paranormalium.pl/ilustracje/archiwum_player/upscaled/48_cover.jpg</link>
<url>https://www.paranormalium.pl/48,aud</url>
</image>