My feedbackID is: FB9631338 . I filed it against WebKit but this could be an issue deeper in the platform.

We have worked around the issue for now buy switching to cordova-plugin-advanced-websocket which uses socket rocket internally and at least doesn't appear to trigger the same platform code we think has the bug in it.

As noted above we switched to the socket rocket based advanced-websocket and it's been meeting our needs so far.