Another thing could be that rvm doesn't trust your rvmrc. Please trust it manually again with
rvm rvmrc trust DIR
After an update, RVM seemed to be ignoring all my .rvmrc files. I eventually got it to work by running
rvm reload
Are you sure rvm is loaded correctly? According to the docs
type rvm | head -1
should show
rvm is a function
The rvm script referenced in you ~/.zshrc is only executed if it exists. Otherwise it's skipped silently.
~/.zshrc