the alt attribute is causing the html to not validate properly. Here is a test to ensure it does not show up anymore:
[expand title="Expand all" swaptitle="Swap all" trigclass="setall" rel="main" notitle="true"]this is a test[/expand]
Expand all
this is a test
With SwapAlt:
[expand title="Monkey" alt="click for donkey" swaptitle="Donkey" swapalt="click for monkey" notitle="true"]this is a test[/expand]
Monkey
this is a test