Vertical grouping & ungrouping process slow

hi all,

Having an odd issue of excel taking +- 2 seconds to recalculate when grouping or ungrouping a batch of rows.

The workbook is rather small around 600kb and is quite efficient wrt formulas i.e. instantaneous automatic recalculation when updating cells in any of the tabs.

I do not have the slow recalculation issue when grouping/ungrouping columns.

The sheet in question feeds another tab in the same workbook via sumif formulas contained in the other tab.

When i make a copy of the tab in question i do not have the issue until i relink all the sumif formulas (+- 6000 in total).

Has anyone else had this issue? I've worked with much larger spreadsheets with many more formulas and not had this issue.

Luckily not. Only simple sumifs and a few vlookups