It does work, that’s for sure. If you want to write out an exact step by step sequence of what you are doing, starting with no note expression data in the notes maybe we can help you understand what to expect.
If the Latch Buffer is disabled and you start to record, the value of the CC jumps to the position at the moment, once you move the hardware controller. So within the note, you can see the jump from the old value to the new one.
If the Latch Buffer is enabled, the very first incoming MIDI CC value is extend to the very beginning of the MIDI Note (ex post, of course). So you don’t see this jump from the old value to the new one.
But here on my side (and I understand, you get the very same result), it seems like the Latch Buffer is always enabled, right? So you can’t get to the state, of the “jump” from the old (already written) value to the new one.
Moreover, if I try to record in the cycle, it seems, only the very first record is taken in account. I can hear the following records (incoming MIDI data change the sound), but they are not written/recorded.