Audio recorded from external synth offset from MIDI

My issue is so basic that I’m sure I have to be doing something wrong. Any suggestions are welcome and appreciated.

My config: Mac Pro, MacOS 10.10.3, RME UFX w/ latest driver 3.27, latest Cubase 8.

Repro steps:

  1. Create new session.
  2. Create MIDI track routed to external synth.
  3. Create audio track recording from external synth.
  4. Draw in some MIDI events exactly on the grid.
  5. Record enable the audio track and record the selection. (MIDI will play, audio will record.)

Observed result: the audio recorded from the synth is offset from (later than) the corresponding MIDI events.
Expected result: the audio waveforms and MIDI events should line up.

This makes it impossible to work with external devices and a mix of active MIDI tracks and audio recorded from previously active MIDI tracks.

n.b. On the exact same system with Logic Pro X, the audio waveforms and MIDI events line up exactly.

Any ideas?