Assets with renditions (thumbnails) are not available for download in dispatcher cache

Hi there.

We have the following scenario:

- Dispatcher instance, we're caching for performance + security.

- Publisher instance

Let's say we request an asset http://site/content/dam/assets/brochure.pdf, this will get cached in our dispatcher dir and will be available normally.

Now let's say we request an asset's thumbnail http://site/content/dam/assets/brochure.pdf/jcr\:content/dir/brochure.jpg, this also will be cached in our dispatcher, but the first pdf will no longer be available for us.

We don't know why this is happening, but any asset with thumbnail will create as a directory within our cache, not as a file; and will respond a 404 when requested as http://site/content/dam/assets/brochure.pdf

We've tried to delete dispatcher cache directory, but it refreshes the same way. Is there a way to debug this? Maybe within dispatcher configuration?

 Thanks!