Subtitles disappeared, in Merge-Mode

[jinjin_jp]

I want to make one disc of Blu-ray from several episodic discs.
The title is "Thunderbird are go".
I tested with 2 episode, before making from all 13 episodes.

Procedure; I output 2 episode each by MainMovie-Mode,
next I merged 2 episodes by Merge-Mode.

The result; there's not displayed any subtitles even if selecting subtitle.
Output of MainMovie-Mode is rightly displayed subtitle.

I want to request the problem is fixed.

I'll attath intermal_log file.

Regards.