The cells in rows marked with "cellsAutoUpdated: true" will be updated on every change, including a row removal.
You might want to review and update the calculation logic. The tutorial (https://code.daypilot.org/93064/javascript-scheduler-column-summary) uses events.forRange() method to find all events for a range:
var events = dp.events.forRange(args.cell.start, args.cell.end);
The current implementation of events.forRange() returns all events in events.list, regardless of the resource.
To include only events from visible rows, you will need to change the the logic. Example:
let events = [];
dp.rows.all().forEach(r => {
const eventsFromThisRow = r.events.forRange(args.cell.start, args.cell.end);
events = events.concat(eventsFromThisRow);
});