Batch Rename changing file type

I batch renamed a small selection of files, and it destroyed the file types... changing to an unreadable, not even real file type "24_JULY2024_##", which is a segment of what I was renaming each file to.

I thought I had lost all these edits, but was able to fix it by manually, tediously, going through and renaming each file and adding ".jpg" onto each one.

Note: it only did this on the 20/22 of the files.