For what reasons would a bbt spike not match up with other charted fertile signs, (including eggwhite cm, high/soft/open cervix, and positive opk)?

Not reliable : basal body temperature measurement is very unreliable. Your ovulation predictor kit is a much better Marker.

BBT: Basal body temp. can be influenced by a lot of things including just getting up and moving around before checking your temp. or any of a number of minor viruses that are going around at this time of year so it is one of the least reliable of the methods of determining ovulation. If everything else says you are ovulating, you are ovulating. Hope this helps.

Varies: The BBT will spike (or drop) depending on a myriad of factors including physical activity, medications, viral infections, state of hydration, etc. The value of the BBT chart is really to help determine, in retrospect, the approximate timing of ovulation during the cycle. It does not predict ovulation as the increase in temperature occurs after ovulation. It will remain elevated with conception.