We have provided a fix for this issue in internal build 8.0.5706.0. So, what I can suggest in order to resolve the issue is to upgrade your Sitefinity project to the latest internal build of Sitefinity 8.0 where we have included the fix. Please refer to the following documentation article
for more details about the supported upgrade procedure.
Please note that you can download the latest internal build for each Sitefinity version from your Sitefinity.com
account in section Products & Subscriptions -> Latest Internal Builds
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Sitefinity CMS Ideas&Feedback Portal
and vote to affect the priority of the items