A new page was inserted but the amount of overset text was not reduced

This is caused by EasyCatalog trying to insert an item into the text flow that is deeper than the frame that it is being paginated into and cannot break across pages, this is typically caused by an item set to ‘Insert’ as ‘Inline’ in the Pagination Rules panel.

For example a text frame with a populated table inside that is deeper than the page and is being inserted, as ‘Inline’ would need to be ‘Insert’ ‘Frame Contents’. This will insert the table as a text character into the text flow allowing it to break across pages rather than trying to anchor a text frame into the text flow.

Another example would be a group of items that are set to ‘Insert’ as ‘Inline’ that when populated, is deeper than the page. To overcome this problem ungroup the items, anchor them within a text frame and then set this frame to ‘Insert’ ‘Frame Contents’.
EasyCatalog Pagination Module - Deeper than page