I've never had an issue with this before that I can recall but it could it be the actual length of the name or that the disk one and disk two part of it aren't at the end of the name
Instead of using Fruits Mahjong 1 - Disk 2 - Mahjong Game Hontai (Japan) (Unl) try Fruits Mahjong 1- Mahjong Game Hontai (japan) - Disk 2
also are these the only multi disk games you have that have two region specified that was why I left the (Unl) out of the example file name I typed. Now that LB handles region tags maybe it doesn't like it if a game has more than one or maybe UNL is one that it doesn't recognize I really don't know just spitballing theories.