Replacing finds more entries than are present

I used a subfolder for storing pdf-files to a subject and selected that subfolder while adding entries and links to the pdf. However, when changing the subject and consequently the subfolder I noticed that the links became unvalid. That’s why I used “replace” on the file entries in a bib-file to get the pdfs available again.
I looked for the “:” and replaced it with “:Metabolism\”. This worked fine. I do not understand, however, while the program tells me that it found and replaced 419 instances when there were 121 pdfs linked. This is something like a miracle. the library itself has only 215 entries.
If this is a bug, please let me know. I can make a bug report and the library available.

Regards Bernhard