When using v[1-9] within folder names it can sometimes cause ambiguity and lead to broken URLs on your website. The reason is that, for example, a folder named v5 (after the band, of course) can also be parsed as an attempt to "version" a resource number "5" over the base image.
To be on the safe side you should be sure to obey to one of the following:
- Avoid using "v[1-9]" within the folder name.
- Use versions to isolate the public ID from the transformation section.