There are two Thai actors listed in the movie entry of SWORD OF EMEI:
1. Chaiya Suriyun
2. Mitr Chaibancha
Summary:
Due to Mitr Chaibancha's sudden death, the leader actor was changed to Chaiya Suriyun
It looks like the Hkmdb information was copied from this website in the exact same wording:
https://www.thaiworldview.com/tv/thaihk2.htm
The problem:
SWORD OF EMEI was released in 1969, but Mitr Chaibancha died a year later, so there would have been no need to replace him with someone else. Also, replacing Kenneth Tsang would have meant to reshoot about half of the movie, doesn't make much sense. Although there was at least one case of replaced HK actors for the Thai audience (Flyer & Magic Sword), but that was a supporting role only while the Thai leading actor starred both in HK and Thai versions.
I emailed the admin of Thaiworldview and he replied that he "might have" made a mistake and that he can't recall his source of this information anymore.
I will delete the Thai actors and the summary note in 1-2 weeks.