Also, for me it always works from the front panel, and from the block diagram if I try it twice. (If I try it four times in a row, it works on tries two and four.) If you guys are seeing anything else in terms of patterns, let me know. I'll try to replicate those patterns as well.
You're right. It does work once in awhile. But I didn't have any real pattern to it. It failed to work far more often than it actually did.