Yes, I know that this is an extreme case, but it happened to us (me and @Jei).
When you try to load multiple (1+) webviews at the same time with same local URL, the listeners provided by the XHR bridge (ti-injection) works only for the first one instantiated.
I debugged for hours, and finally realized why this happens.
The LocalProtocolHandler class implemented in the Webview communication receives only the first URL to load; and this causes only one injection with the same Ti.pageToken.
In this screenshot you can see that the generated pageToken is the same:
The solution would be to inject a new header that has a unique counter thats incremented every time a new local URL is set.