The ZoneMinder and Apache logs are free of anything other than normal, healthy function notices. I realize the images are large (I have five IP camera's at 704x480 running), but the quad-core processor with 8GB of RAM still isn't breaking a sweat, so to speak. I can record at 2 FPS or 10 FPS, and the same issue still occurs.
Included are two good examples of this occurring - shown are two sequential still images. Note that the times are during the same second. The rest of the stream for these events sails along smoothly at 10 FPS.
Any idea as to how to remedy this, or settings to try so as to narrow the problem down more precisely?
Me walkin' the dogs (alas, my house is painted pink - previous owner's idea, will be fixing that shortly!):


The maids:

