MIDI Timecode and Tempo

[bigbadotis]

Tempo automation doesn't work if you have MTC enabled for sync and the EXT button pressed. This doesn't make sense to me: since MTC is always coming in at a fixed speed and can't transmit tempo change information, why would the tempo be locked to it? I can understand why this behavior would exist for Midi Clock, but am confused about why it is there for timecode.