If changing the checkbox state "organize my uploads..." in the media preferences the thumbnails aren't shown anymore

[anonymized_13423376]

Hi i ran into the following issue on WordPress 4.2.2. The steps to reproduce.

1. Inside the media preferences keep the checkbox "Organize my uploads into month- and year-based folders" unchecked.
2. Upload one or two images inside the library -> everything is previewed properly in thumbnails as well as all files are properly uploaded when checked via ftp.
3. Now check the "Organize my uploads into month- and year-based folders" checkbox.
4. Drag and drop a new image to upload inside the library.
5. The thumbnails for the images aren't shown in the library. You only see questionmark placeholders.
6. But if you check via ftp the source files are actually there inside the designated yearly and monthy subfolders but as mentioned not shown in the library.
7. if you uncheck the checkbox in the media preferences again and upload a new image everything works out again and the previews are shown again.

Cheers r.

[swissspidy]

Just tested this on a local install running trunk and couldn't reproduce this.

Does the issue still appear on your site, even with all plugins deactivated?