When using wildcards in tag filters, the searched tag is shown twice for some patterns.
For example
http://stackoverflow.com/questions/tagged/*facebook*
results in showing the Facebook tag twice:
Another example showing the searched tag twice:
http://stackoverflow.com/questions/tagged/*magento*
The issue seems to somehow depend on the tag being searched.
Other patterns, like:
http://stackoverflow.com/questions/tagged/*html*
http://stackoverflow.com/questions/tagged/*http*
work as expected. They do not show the searched tag twice.