I’ve noticed an issue where any posts that use a redgifs backed image don’t show correctly and just have an “unknown” icon. If I click on the “view externally” link in Voyager it’ll take me to the webpage that displays it correctly. I don’t know if this is because Voyager has an issue displaying it, or the instance customized their UI to display it.
Sounds like a bug if that didn't help.
Maybe try logging off the app and back on. Just a guess