So after some deep digging, I finally discovered that it is a problem with
- rails_stdout_logging gem
- paperclip gem
- paperclip config with S3 storage
- jbuilder
With the combination of those 3 things + using the paperclip object instead of the url (i.e json.node_name my_model.paperclip_attached_file instead of json.node_name my_model.paperclip_attached_file.url) made it fails.
Now seems to work faiirly…
So Matthew were right on target saying that the picture was the problematic one, but only with rails_stdout_gem + paperclip S3 config