I only know jitter from electronics as well, but it could be applied in mechanics as well. Iirc, jitter is the irregularities in the intervals in a periodic signal, like data transfer. But jitter will be present in anything with a period, it doesn't have to be digital signal. A jerk is a single action, so there is no period and there can be no jitter. A series of jerks could have a seemingly regular period, but when measured more accurately, the intervals between jerks will have small variances: jitter. Hence why imo a series of irregular jerks could be considered jittery.

Noone ever uses it that way though and I'm not even sure that I phrased it correctly, but because of the word "jerk" I find it a mildly fun play on words.