No, it’s because the front end is all JavaScript so it runs client side. In fact, once you’ve accessed SOTAwatch there’s no accessing the server again until you do a forced reload.
The API, which supplies the spots to you, is what determines what is displayed. It’s highly unlikely that if one client is seeing the spots and another isn’t, that it is an API issue.
I’d clear cache and cookies and do a full reload, or try via private browsing/incognito if you see it again, which will confirm if it’s cache or not