File existence status is not updated in the cache after an operation which changes it for a given filename (e.g. move, delete), which causes weird errors (files do not disappear but become broken on delete; the file is displayed on the redirect page but not displayed on the new page after move). Purging the file fixes it.
During move, the file is not properly moved to new filename, only description page entries are.
Problem appeared today (2015-03-17) about 17:57 UTC, Concerns, for example, all entries from:
moved between 2015-03-17 18:57 UTC and 2015-03-17 19:13 UTC
Moving the image back, deleting & restoring does not retrieve the file entry (only description page entries are available for restoring)