Mapped midi transport and other midi functions not working as expected.

I have a Nektar Impact LX25 that I used to use for note entry in Musescore 3. However, something has changed with MuseScore 4. The best description is that in MuseScore 4, the mapped midi transport keys work only when pressed and held. They do not function as toggles as in MuseScore 3 where press once to engage, press again to stop the function.

For example, if I press the mapped "Play" on my midi keyboard, the playback continues only if I hold the key down. On my text keyboard, the space bar functions correctly as a toggle. In MuseScore 3 the midi transport "Play" functions normally as a toggle.

I have the "record" transport midi key mapped to "Note Input". Again, I have to hold the record button down while I enter other notes. It does not function as a toggle, as it used to in MuseScore 3, or as pressing "N" on the text keyboard.

Interstingly, when I map "Note Input" to a variable pot (CC74), I can twist the knob around until the Input stays on, enter notes as usual, and then twist it again until the Input turns off, or press the "stop" key. A weird work around...It would be nicer if things worked per normal. This fix also works to get around the non-toggle "play" and "loop" transport keys using other pots.

Also, when NOT in note entry mode, pressing keyboard keys with MuseScore 4 results in the sound playing very briefly and then quits, which makes it difficult to assess chord voicings and the like.

I checked using Szforzando stand alone app, outside and within MuseScore 4 to see if my keyboard was the issue. In Szforzando outside of MuseScore 4, the keyboard functioned normally--pressing and holding keys produced a held note sound. However, repeating that test using the Szforzando vst instrument within MuseScore 4, it replicated the errant MuseScore behavior, so it is definitely something in the MuseScore 4 midi interface causing the issue.

Anyone think of what I might be doing wrong, or is this a reportable issue with MuseScore 4? Like I said, testing with MuseScore 3 reveals correct behavior with all settings the same.

Mac MI Mini using OS 14.
Thanks.