Security problem?

I just right-clicked on a Calendar task and noted that the Services listed had somehow changed language to what looks like Portuguese. In going to the Services Preferences pane there were many entries of Services that were in Portuguese. When I restarted the computer and checked again all the Services entries reverted to English.

Is this a known problem within iOS Lion, or is this an anomaly that I should be worried about as a security matter?

I wouldn't be concerned about it. It's certainly not a security matter in any event. You might want to open System Preferences, Language & Text, Language tab, and check to see what order the languages are listed. You can set that to only display English if you like.