I just experienced a situation where Bridge messed up some, but not all, file extensions during a batch rename. It's similar to some other threads I found, but different enough that I thought I'd start a new one.
I have a folder with about 175 items. There are CR2 and JPEG files from two cameras, and HEIC files from an iPhone. When I did the batch rename, several, but nowhere near all, of the CR2 files, and a couple of JPEGs, got assigned the HEIC file extension. And some of the HEIC files were given the CR2 extension. There seems to be no rhyme or reason. As you can see from one of the screenshots, consecutive RAW files were given different extensions. My rename setup did not involve altering the extension at all. On top of all of that, about 8 files did not get renamed at all.
Now, I can't undo the batch rename, and will have to take a great deal of time going through and fixing them. Anyone else have this problem, or know a remedy?
P.S. If you tick the "preserve filename in XMP" checkbox when renaming, then you can easily restore the original filename if something goes wrong. Also use the preview button to preview all files being renamed, don't just rely on the single file preview.