I've noticed this problem since I started using Akiflow - I use a lot of recurring tasks which use the "custom repeat" (e.g. for medications that I take every other day), but for some reason when I schedule these tasks they will be assigned an arbitrary end date, even if I specifically chose for the task's "End" setting to "Never". How to reproduce this bug: Create a new task. Click the task, then click the "recurring arrows" button. Select "Custom Repeat" Select for the task to repeat "Every 3 Days" with "End" set to "Never". Apply this to all future tasks. Go back and look at the task's recurrence setting - you will see it will be assigned an arbitrary end date in the future (the one I created for this example was set for 1 year from today, but I've seen it vary). If it helps, I'm on Windows / Android.
