When issue comment contains '&' sign RSS XML response is not properly encoded.
Any client application that tries to read that not well formed XML response explodes.

I attached XML response from Customer. The RSS urls is like this
http://HHHHHHHHHHH/sr/jira.issueviews:searchrequest-xml/IIIIIIII/SearchRequest-IIIIIIII.xml?sorter/field=&sorter/order=&pager/start=0&tempMax=25
WHERE:
HHHHHHHHHHH - replace with your JIRA host ie. your.jira.address.com:8080
IIIIIIII - replace with saved filter id this is an integer value ie. 100000.

related issue https://studio.atlassian.com/browse/PL-2477