Incredibly, PRC film censors insist that HK's Cantonese film scripts must be translated into Mandarin to vet HK films before they can be approved for screening in the Motherland, reports SCMP:

[Film Development Council's] Wong, who took the helm in April this year, said local filmmakers needed to translate a Cantonese script into Mandarin and submit it to Beijing authorities in order to screen Cantonese-speaking movies on the mainland.