The key problem is, Android is a front-end technique. Everything you put in code/resource is transparent. But so many developers treat it like back-end and believe it's save to put sensitive info inside...
The key problem is thinking anything the client does is secure, or even worse, that it may be trusted. A developer that hasn't grasped this very simple fact will inevitably not only screw up the client side (i.e. exposing AWS credentials), but also the server side.
This vulnerability exists with EVERY client application. It is just much easier to obtain the applications with android(as opposed to IOS) which is the only reason i can assume Trustlook focused on android.
This isnt as much a "vulnerability" as it is a complete miss understanding of security and the technology they are using. Everything on the client side should be assumed as obtainable.