bundle config set --local path 'vendor/cache'
generally fixes it as that is the more common problem. Basically, your bundler path configuration is messed up. See their documentation (first paragraph) for where to find those configurations and change them manually if needed.
P.S. If the documentation link is not accessible it might be related to the bundler version, in that case you can move to main page and search the topic instead e.g. bundle-config from https://bundler.io/v2.4/man/bundle-config.1.html