After a week and a half of random poking and prodding at different parts of the CMI-01A "Channel Card" emulation for the Fairlight CMI IIx driver in MAME, I finally managed to isolate and fix the sample issue that was affecting ITCH.RS and MILLION.RS.
Without getting too far into the gory details, it turns out that the Motorola 6840 Programmable Timer Module (PTM), one of which exists on each Channel Card and one of which exists on the Master Card to drive primary tempo-keeping, ticks on the falling clock edge when clocked externally, not a rising edge.
For certain particularly long samples, this resulted in the sample either being far too short, or far too long. With this sequence in particular, the "LOSTR3" sample would re-trigger towards the very end of the whole note when played at its highest pitch (as this runs through all 16k worth of individual sample bytes), and the "TBMILCLP" sample would occasionally play as just an abrupt click rather than the expected clap patch.
The one remaining issue is that the "MOOGTRIG" 'sample' seems to emit an audible click when triggered. Most likely, this specific channel was used to trigger events on an external Moog synthesizer during ABC's performance of "(How to Be a) Millionaire" on UK TV programme called "The Tube", back in 1984; due to the very short nature of the click, the most likely scenario is that it ended up being rendered inaudible by the Channel Card's Curtis SSM2045 filter chip, which is not yet emulated here.
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