Scrub does not play all Arp notes in Mode T1 or T2

[beau-seidon]

Describe the bug
The scrub knob does not play the extra note, 1 or 2 semitones above, in trill mode.
In all other modes, scrub plays all notes generated by the arpeggiator.
In Trill mode, Scrub plays all held notes in all octaves set by Range, but not the extra trill notes.

Steps To Reproduce
Steps to reproduce the behavior, e.g.:

1. Start with (or reset to) a basic patch.
2. Set Arp to Mode T1 or T2.
3. Turn Arp Rate and Range knobs to 50% and play a chord to hear the "trill" effect.
4. Turn Arp Rate to 0, and manually sweep the Arp Scrub knob from 0 to 100% with same the chord held.
5. Listen for the difference.

Actual behavior
Only notes that are actually pressed on the keyboard (and their higher octaves determined by Arp Range position) are sounded.

Expected behavior
I expected to hear the extra notes 1 or 2 semitones up, in addition to the held notes and the higher octaves.

[beau-seidon]

Another test is to set Rate and Range to 0% and sweep the Scrub knob back and forth between 0 and 100% with a note held.
It does nothing.
Below 50% it should play the pressed note, above 50% it should play a note 1 or 2 semitones higher, depending on Arp Mode.

[beau-seidon]

I just noticed by pressing the same note on my keyboard repeatedly in various Arp Modes including T1 and T2, with Rate at 0% and Range in different positions, that the output seems to cycle through notes in the Arp sequence each time the key press is repeated.

There's obviously some built in behavior that I don't yet understand, so my bug report might be invalid.