Stuttering on Playback/Mixdown

[midwinter]

Hi.

Everything was working just fine last night, but this morning after I did a little editing (I had a rogue vocal track playing over the punch; I deleted the original one and moved the punch to the right place), playback and mixdown on the first half of a song have some light stuttering. It happens with all tracks frozen. It happens with most tracks muted. It doesn't happen on any other projects. This is an iPad 3 with plenty of space. The CPU is never pegged.

Advice?

[midwinter]

Nevermind! I got it fixed and all is back to normal.

[midwinter]

Hrm. Well it seems that Auria wants to have two empty tracks in this project. If I delete them, the stuttering comes back. I didn't add them. This is the same project. This morning, they were added on the right-hand side (say, tracks 9 and 10); right now, they're on the left (tracks 1 and 2).

Any thoughts?