Sorry to hear of the problem you are having.
I have tested it on my test site but I am not getting the error message using below latest version of Gillion theme.
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This can be due to plugin conflict on your site so please try temporary deactivating all plugins except Unyson plugin and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.
Could you please share me the page URL from your site where the error is displaying so that i can troubleshoot it?