I don't know the cause of the crash, however cronet is provided by Google, who describe it as:
Cronet is the Chromium network stack made available to Android apps as a library. Cronet takes advantage of multiple technologies that reduce the latency and increase the throughput of the network requests that your app needs to work.
https://developer.android.com/guide/topics/connectivity/cronet
My guess is they've got some unusual crash related to their library which is being used in your app somehow (perhaps even in the Firebase Crash Reporting SDK implementation?).
As you reported this crash 6 months ago I hope you've found a workaround or fix. Please do add an update here.
If you're still suffering from the issue, try raising a bug report with Google. The same web page says:
You can send feedback about the Cronet Library using the Chromium Issue Tracker. Check the list of bugs in the issue tracker to make sure that your issue hasn't already been reported. If your issue hasn't been reported, file a bug with the word Cronet in the summary line.
All the best