Unreliable message sending (upstream presage issue)
For some users (such as myself), Flare may be very unreliable at sending messages. This can include messages sent from Flare sometimes not showing up in the Signal Android app, messages sent from Flare sometimes not showing up in Flare on other devices, and messages sent from Flare sometimes not being received by recipients.
This is an upstream issue with presage, the library that Flare uses to interact with Signal. As such, it has been reported there. This is essentially a tracking issue that will follow along with the progress of the upstream presage issue.
So far, the issue has had multiple attempts to fix it, but none of them have been successful. The amount of users affected by it also seems to be only a small part of Flare's user base, judging by the number of issues reported in the Flare repo (up until now, none) and the amount of reports in the Matrix room.