I feel like this is kind of a big issue that I just happened to see.
Problem: Impact of Google Chrome and Microsoft Edge 127 Updates on ArcGIS Enterprise (esri.com)
Yes, I did. I actually re-applied the patch last night and it fixed the issue.
Has anyone had this issue even after the patch was applied? I applied the patch back in July, and just this morning my navigation menu disappeared.
Try to re-apply the patch again. I had issue with banner after I applied the patch, so I re-applied it. So far, it's been fine. Also, what ArcGIS Enterprise version do you have? There's "Portal for ArcGIS Security 2024 Update 2" patch released a few weeks ago for 11.2, 11.1, 10.9.1, 10.8.1, this patch does include the banner one. So if you haven't apply this patch yet, apply this patch and see if your banner issue will be resolved.