As a general recommendation you should not include puntuation characters in Passage Names. I would suggest using the following Markup based Link variation whenever you need such characters in the Link Text, and to exclude those characters from the Target Passage Name.
[[Link Text->Target Passage Name]]
What your are seeing is a limitation of Harlowe's syntax highlighter when it comes to recognizing the contents of a Markup based Link that contains a coma, and switching to the above recommendation will not resolve this limitation.
You could replace that specific Markup based Link with a (link-goto:) macro based one, however that will remove the associated connection arrow in the Story Map.
(link-goto: "task, 1", "Target Passage Name")