dyscalendia 

Analogous to dyslexia (bad with words) or dyscalculia (bad at math).

Etym; dys (bad) + calends (Roman 1st day of month, when rent and bills are usually due) + -ia (state or disorder).

Means one has trouble keeping appointments.

With my dyscalendia, I'm often too early or late for salon or doctor visits.

dyscalendia by AmboNec December 30, 2021

Discalendaria 

The inability to read calendars accurately.

Rob showed up to the company picnic on Saturday opposed to Sunday because he has discalendaria.

Discalendaria by Guaca_Molly August 5, 2016