One could start connecting top and bottom parallel lines to form the channel.
Nov 7th, 2018 and Jan 25th, 2019 the first two points for the top of the channel.
Oct 30th, 2018 and December 21st, 2018 the first two points for the bottom of the channel.
With that reasoning, the August 2018 gap should fill as it makes it way to the top of the channel: This should happen next week.