Hard to say if it’s a bug or a problem with the Internet.
In the past week I’ve experienced many problem with Internet related services, in general, ranging from intermittent availability to lag times (many web pages often can’t load CSS files or images). A quick search revealed that the COVID19 lockdown in some geographic areas is responsible for this — lack of adequate servers maintenance, etc. So much so that even major players have temporary reduced some services (e.g. WhatsApp has temporary reduced the number of video conference participants).
So chances are that it might be due to temporary network problems — summer time is always problematic for network services, with many people being on holiday, and partly due to the heat affecting many devices; add to that the fact that since the COVID lockdown more people have been connecting to the Internet (online school classes, employers working from home, or just people having more time to watch streaming TV) and the reduced labor force to maintain infrastructures, all of these making this summer worst than others.
The Travis status on GH’s WebUI is quite entangled, which doesn’t help — e.g. sometimes the status badge images won’t refresh on the repo README by a simple F5 page refresh, clinging to the cached image instead of the latest one. But the Travis email notifications are always reliable — but again, as of lately some emails take very long to reach destination (e.g. last week a purchase receipt from a huge corporation took three days to deliver).