Yes and no - there is indeed some issue with how Firefox's autocomplete is implemented, but it also depends on the keyboard in use, as the issue you're describing certainly doesn't happen with every keyboard app. I still have a slightly older version of the Xperia keyboard lying around on my phone from looking at bug 1344464 and while I can only get it to say /r//popolitics, maybe that could be enough in tracking down a fix if I find some time.
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Yes and no - there is indeed some issue with how Firefox's autocomplete is implemented, but it also depends on the keyboard in use, as the issue you're describing certainly doesn't happen with every keyboard app. I still have a slightly older version of the Xperia keyboard lying around on my phone from looking at bug 1344464 and while I can only get it to say /r/popolitics, maybe that could be enough in tracking down a fix if I find some time.