On one of our Catalyst 4507R's, one of its VLAN interfaces went into shutdown mode apparently of its own accord over the weekend, which threw off a lot of IP routing. This switch is running IOS 12.2(25)EWA6. It has been up for about a year and a half, and has had no config changes in over a month. There is nothing in the logs that would indicate any errors that might have caused this.
Is this sort of thing very unusual? It's certainly the first time I've seen it. Does anyone have any ideas what might have caused this or whether there's anything I can do to further diagnose the issue?