1) In logarithmic scale, exponential functions appear as straight lines.

2) You are reading way too much into a random pattern.

If you zoom out more, you will see that this IS a not-random pattern, there are transactions with regular spacing and value decrease, that results in a line, and they started exactly at 12:00 (on the graph, I dunno what timezone it is).

The vertical lines, maybe are coencidences, but the decreasing straight line certainly is not.