I have a Canon B500 and when I take pictures say, over a weekend, I often end up with multiple folders with names like 100NIKON and 101NIKON, and within those folders I get my JPG and MP4 files, all with names like DSCN1056.MP4 and DSCN1057.JPG. Normally the camera wouldn't create a new folder until I had taken quite a few new pictures and movies. And even then, the file names have always continued to go in ascending sequence, as if there was an internal counter. My normal process is to get home, copy those folders off onto my NAS, and then delete everything on the SD card. Typically I've just use Windows File Explorer to delete all the NIKON10* folders. Then, once I start taking pictures, the camera would create a NIKON100 folder and start adding files to that folder with the ascending numbers. This weekend, however, the camera stored things differently. At first, it did indeed create the NIKON100 folder and started adding files with the next ascending number. I didn't take that many movies/pictures and I expected to see them all in that same folder by the end of the weekend. However, at some point the camera started behaving differently and instead created new folders (NIKON101, NIKON102, NIKON103) each with far fewer files than I would have expected, but even more unusual, renumbering kept restarting at DSCN0001 for each folder. I assume I've changed a setting somewhere, but where might that setting be? Thanks in advance for your help!
I don't think that you are shooting with a Canon B500. The B500 is a Nikon and this is a Canon Forum. Maybe you should post at https://www.nikonforums.com/forums/
BTW, The camera may be creating different folders if your switching between modes like still, video, panorama, etc.. You are right to think that they would mostly stay in the same folder until it has a large number and then becomes a bit of a processing power issue. I did notice you say your removing folder through the computer, I highly recommend using the format feature on the camera after you are done transferring. A proper format in camera, will apply a fresh directory structure, and is recommended by the different camera manufactures. I'm not sure if that could make the multiple folder situation more pronounced, but it is possible.