It is a known issue that the webpage update does halt the scrolling display for a moment,
Unfortunately, this cannot be prevented, only shortened with optimizations, such as reduction of 'String' usage.
Also, in an environment with low WiFi signal ( < 30% RSSI as indicated on webpage ), it is possible that scrolling text is halted or very slow, even when the software isn't actively connecting to a web server.
This can also not be prevented; the WiFi stack is connected to your access point and tries to maintain connection autonomously.
To reduce chance, close any web browser (-tab) that connects to this device.