Monitoring - Support for Messenger plugins on Safari 12 has been temporarily disabled by Facebook. This affects web growth tools that use Send to Messenger button or Checkbox Plugin only when the user is using Safari 12.
Facebook team is actively working on addressing this. Unfortunately, they do not have publicly available ETA on this feature.
Resolved -
Although Facebook bug report still isn't closed, we have monitored the situation for 2 days and can confirm that webview is working without issues again. For this reason we are marking this case as closed.
Monitoring -
Webview is working properly again.
Nov 10, 00:27 PST
Investigating -
There is a problem with opening webview from Messenger on desktop due to certain issues on Facebook's side: Payments, Date Picker User Input, URL buttons with Webview Size set up are affected.