Rss problem on theme support

Hello,

We have a problem on the RSS page of the support forum for a theme we have.

https://wordpress.org/support/rss/theme/zerif-lite

We have a system that checks for new support topics using the rss feed from the above url. Since a few days ago it started to report errors with parsing that feed and when i access directly that url i get:

http://prntscr.com/695o0l

Also the error that our system is reporting is:

An invalid XML character (Unicode: 0x1f) was found in the CDATA section.

Anyone know what problem could be ?

Thank you !