Same thing happened to me.
I have Virtue Theme Premium.
Settings:
– The language is set from the directory name in pretty permalinks
– static home page
If i set ” The language is set from content” portfolio works BUT strings translations doesn’t.
If i set “The language is set from the directory name in pretty permalinks” portfolio doesn’t work, everything else is ok.
I tried the development version and it didn’t work. Besides i had to configure all language settings again when i reinstalled polylang old version.
I hope polylang next version fixes these problems!!
Thanks in advance