Expected behavior

I expected to be able to enable in-app notifications on any posts in the Reader.

Actual behavior

When I try to enable in-app notifications on some posts, the toggle immediately toggles off. I noticed it happening on a blog (internal p2) where I already follow all posts and comments via email.

The app logs show the following:

2022-07-01 12:57:21:712 🔵 Tracked: reader_toggle_comment_notifications <blog_id: 208157483, default_tab_experiment: dashboard, notifications_enabled: 1, source: reader_post_details_comments, subscription_count: 96>
2022-07-01 12:57:22:037 Error updating notification settings for followed conversation: Optional((extension in WordPressKit):__C.ReaderPostServiceRemote.ResponseError.decodingFailed)
2022-07-01 12:57:22:038 Reader Comments: error toggling notification status: Optional((extension in WordPressKit):__C.ReaderPostServiceRemote.ResponseError.decodingFailed))

Steps to reproduce the behavior

1. Follow all posts and comments on a blog (this can be adjusted in the following settings in https://wordpress.com/following/manage)
2. Find a post from that blog in the Reader.
3. At the bottom of the post detail, tap the bell icon.
4. In the bottom sheet, toggle on "Enable in-app notifications".
5. Notice the setting immediately toggles off. When you close the bottom sheet, a notice appears with the error "Could not enable notifications"

Tested on iPhone 12 Mini, iOS 15.5, Jetpack app 20.0.1