Had an issue today where menu_block module wasn't showing when clicking a link to a view with argument.

Example: 

create a view with path 'my-view' and add a node id argument

create a link in a menu to my-view/1   (or whatever node you want to link to)

create a menu block on the menu where you created the link

clicking the link will not show the menu block

change the view path to my-view/% and all is well

Assume this announces the trail...