New entries not appearing in TimeMapper, old entries disappearing

[historyjacobs]

My student is using TimeMapper to study for AP World History. Her spreadsheet includes more than 100 entries at this point, but many of her newest entries have stopped showing up on her TimeMapper, and some older ones have begun to vanish from the TimeMap. Is there a limit to the number of entries? Could something else be going wrong? (Nothing past entry 78 shows up on the TimeMap now.) Here is the spreadsheet: https://docs.google.com/spreadsheets/d/1FKpXVeIZza4Q3qYA0lM5So8VaociDwryMO5iSCabkRo/edit?usp=sharing

Any help would be greatly appreciated!