Extra .!ut added to incomplete file after reloc. in the same folder

[BiBlix]

OS: Vista Home 32 bits

µT: 2.2.1 build 25130

Example:

Option "Append .!ut to incomplete files" is enabled.

2 torrents jobs sharing the same file with a different filename and a different hash: one torrent is public, the other is private.

The torrent #1 starts to download the file file1.ext (.!ut is added normally during the download) and the torrent #2 is stopped.

Relocate the file of the torrent #2 (file2.ext) to file1.ext.!ut and force a recheck.

Stop the torrent job #1 and start the torrent job #2.

An extra .!ut is added to file1.ext.!ut and it's confirmed by a forced recheck of the torrent #1 which fails (0%).

Why does µT add an extra .!ut to an incomplete file already displaying .!ut extension?