Monitor the network logs during one of the classes where the most students seem to be impacted to see if they spot any abnormalities or spikes in the network during that time.
Keep an eye out for Extempore and Twilio. There have been a few districts recently where something related to Twilio was being blocked or throttled.
If Google Chrome and/or mobile applications updates are controlled at the District level, please ensure that devices have the latest version installed.