Help Tasks removed from Calendar app (S Planner)?

[Bas Kroese 1990]

I noticed after the last general update on my phone that my Calendar app (previously called S Planner) has removed all my Tasks. These seem to have been replaced by 'Reminders', but these reminders don't show up at all in the calandar. And I cannot even edit them. They seem to be totally broken.
Is this a known issue?

Best,
Bas