I was plagued with this problem for ages. They are temporary files. My problem is that I was writing a lot of metadata to a file via a VB Macro. The problem was that the bigger the image, or the busier my system, the more likely the temporary file was to appear.
I solved the problem by concatenating all the instructions to write the individual pieces of metadata into one command. It never happens now.
I can only imagine that the continuous opening and re-opening the file was causing the problem.
You may have a different problem, of course, as I do not know how you are adding the metadata.
win 10 prox64 DOPUS 12.12x64
I think the ".jpg11456" are temp files and I'm not finding them in the folder at all, now some time has passed the data might be embedded into the official JPG file.
Reported a similar issue in another post where the file had a mysterious string of numbers after a known extension (PNG) and was not accessible.