That is what I figured. At some point imgur changed something with their mobile website that broke all of the reddit apps at the time the issue occured. Most of the reddit apps fixed this issue, but this app was no longer being updated by that point.
A good solution is downloading an app named "Flynx" which is a browser that will "float" above whatever app you are currently using. Install that and then change the default link behavior in the settings to open external apps instead of using the in-app browser.
Google Play link to Flynx: https://play.google.com/store/apps/details?id=com.flynx
I'll put in a good word about slide for reddit. Active dev, great design, ad free, open source(and you can make it look pretty similar to flow). I've gotten so used to it that I don't even want to try out boost that much, but it's great to see another contender.
What I've been doing lately is using the imgur external app setting in Flow with Chromer to work around the error. Works prettay pretay pretty good.