This is a bug I have confirmed originally posted by Mattcro:
Every version after 3.2.3.3 has had this problem including the latest release.
To summarise what both Mattcro and I have observed:
When using a Roland TD-11 with variable hihat articulation it is not possible to get the fully closed articulation using the settings in the Hihat Response panel.
In BFD 3.2.3.3 I get the full range of open to closed hats sounding correctly, but in BFD 3.4 (with all the same settings for hihat controller and articulation) I only get from fully open to about 1/4 open, and no closed sound.
The TD11 module outputs CC4 values in the range 0 (fully open) to 90 (fully closed), so I’ve got the articulation “closed” threshold set to around 85. I started with the TD11 key map preset which has the closed threshold at 84. I can see in the Hihat Response panel that it is indicating a “closed” articulation, but is actually sounding a 1/4 open articulation.