definitely not far-fetched. I've seen similar behaviour on a number of self-hosted solutions - often it's solved by improving the configuration of the web-server.
One scenario I saw a long time ago - a teacher had uploaded some large video files to their course and rather than downloading them on the home internet connection a students flatmate loaded some form of automated download software on their laptop and pasted in the links to the video files - when that student came on-site and connected to the network the downloader kicked in and tried to download the files. Problem was that the file download required the student login first and it didn't share the session with the users web-browser. The software tried to download all the files at once and made very quick subsequent re-attempts as each attempt failed. This caused a significant load on the windows-based server... A number of different configuration changes were made to prevent this kind of load from taking the server down (it took quite a bit longer to convince them to move off windows but we made it in the end!!)