Strange Copy/Paste behaviour WP 8.1 - windows-phone

Question

I'm developing a Windows Phone 8.1 universal app which allows the user to submit a link to a tweet.
From the Twitter WP app, select a tweet, then select the "copy link to tweet" context menu option.
Then paste that into a normal TextBox in my app and get the link followed by what appears to be Chinese characters. However, these appended characters are not consistent and vary with subsequent copy/paste.
Here are a couple of screenshots to illustrate the problem -
This is an odd one since it spans two distinct areas 1) the Twitter app itself and 2) WP 8.1.
When I paste this into Word it is fine. If I paste the same link into other TextBoxes on my page the strange characters vary.
Here is a couple of examples:
...twitter.com/TomMSFT/status/566885761476460544䓔
...twitter.com/TomMSFT/status/566885761476460544䊰灐ঔ佀玍㜀耀瑨搆玌搆
I've tried setting the Language property of the TextBox to the current culture of the phone (en-GB), no joy. This may be something the Twitter app is doing, if so, is there any way to filter out these characters when they are pasted into my app?
Anyway, this one has really got me scratching my head. Any ideas or help is appreciated.
UPDATE:
As an immediate workaround, I'm applying this solution to strip these out:
private void LinkTextBox_OnTextChanged(object sender, TextChangedEventArgs e)
{
LinkTextBox.Text = Regex.Replace(LinkTextBox.Text, #"[^\u0000-\u007F]", string.Empty);
}

Answer 1

Unfortunately this is a known issue with Windows Phone 8.1 apps pasting Unicode text. Some form of manual stripping (like your Regex) is needed.