Hi, choirguy,
I have never had any trouble getting arpeggios to play, except if I put one on the downbeat of bar 1. Since the rolled chord starts before the downbeat, it can't be accommodated — unless you add a "fake" pickup bar before the rolled chord.
Also, Notion's arpeggios on a grand staff don't behave as they do in real life. I have attached a small file that illustrates both the pickup bar suggestion mentioned above, and also shows how to get a two-fisted arpeggio to play properly in Notion. It's a subtle difference in the test file: the first chord is performed as two simultaneous rolls, one in each hand. The second and third chords are performed as one long roll, one notated in the left-hand staff and the other in the right-hand staff.
Best wishes,
Thorrild