Can you tell what’s wrong with this blueprint graph? (hint: it’s very broken if you call it more than once). I could tell you a long story on how to fix it - but I’ve actually already done that several years ago.
Ok, the answer is that the event parameter “Url” is overwritten each time the event is triggered - hence when the latent action completes it will use the wrong key for the image cache. Although they are called event parameters in the ui and they look like parameters - they actually are not. Instead they are per object instance variables. Beware.
I have exactly the same issue.
If DownloadImage would have a context object as both input and output it would be much easier. Plus the url parameter 
I managed to do it without any code involved:
- Create a new object blueprint
- Add the url, context (pointer to caller) as variables
- Call DownloadImage from there.
- In the async OnSuccess or OnFailure delegate pins, call an event dispatcher with the url and context variables.
All Done!