I get this once a day but never able to track it down. I've added logging now so that the error is at least captured in the console but that only works when the app is running under the debugger, and I can't do that all day.
I do notice, but have no idea if it's related that there are many on-start errors, the most common is
tcp_connection_write_eof_block_invoke Write close callback received error:  Invalid argument
but also this one from time to time
nw_endpoint_handler_add_write_request [32.1 188.8.131.52:443 failed socket-flow (satisfied)] cannot accept write requests
The error.json problem isn't a networking failure, the error view shows up immediately, no time for any networking and looking at my server logs shows that the app didn't make any requests.
I'm curious if anyone else has seen this with their apps?
It happened under the debugger (finally!!!!!!!!!):
callback received error:  Invalid argument
2017-07-19 14:44:01.503332-0700 Jasonette[851:176507] showing error.json The request timed out.
2017-07-19 14:44:01.503437-0700 Jasonette[851:176507] LOCALFILES jsonFile is /var/containers/Bundle/Application/F809F297-0AEE-4905-B82F-CCF4CD09F359/Jasonette.app/error.json
The The request timed out is the error that's causing the failure block to execute, however, it never made any networking request to timeout.