No worries Andrew
Yes, the spikes look to happen regularly, so you are probably right and that is good news. In phd2 you can dither every second sub - it sometimes helps with guiding. It definitely looks like the guide graph from Meade, in spite of being scaled down, also alternates directions for the better part in RA, probably because of seeing moving star's centroid around.
Another possible reason for star elongation is differential flexure between guide scope and the main scope. Orion ST80 is a substantial guidescope and there may be flex between the two telescopes. Is your guide camera supported by a ring or is it simply attached by an extension tube to ST80's focuser? A smaller (and lighter) 50mm guide scope would be perfectly sufficient for guiding ED80. In the years long gone by, before I started using an OAG, my 50mm guide scope was be supported by 3 Losmandy rings and one of them directly supported SSAG so it would not flex.