Maybe they made yellow subs for foreign prints, but without proof I am extremely skeptical. Telecine bootleg--white. 16mm print--white. Home video--white. Plus no one else ever said, "how come they changed the subs to white for the video releases?" Plus the theatrical SE was white.
Could be true, but without something more than the word of one man I would say there's little merit to this claim. Could you quote his statements?