Hey there, I need some help.

So I'm trying to reupload my map, but it doesn't work.
Steam recognizes everything in the map folder (.json files, the map itself, preview image), starts uploading, eveything seems to be in order, but at the end of uploading process cmdtool assigns this huge number 18446744073709551615 as File ID and say "Operation completed!" yet the map doesn't appear in workshop.

I had this issue before, but then I've stumbled on another thread:
https://steamhost.cn/steamcommunity_com/workshop/discussions/-1/517142892068585723/?appid=225140

So I changed the name of the folder and it worked and after that I'd uploaded another map just fine, but right now I'm having this issue again and the folder name is 5 letters long!

I don't get it at all. What's causing it? Can somebody help?