Throws error 'Cell range B3:D10 is not merged' when unmerging cells in the rows inserted on the go

[cmubeenali]

I have a worksheet with 10 columns and hundreds of rows. it is loaded from sql data using np.array. some rows have dependent data i have to show in a new table. as a solution, what i did was inserting multiple rows according to the dependent data row length. i have merged cells from B to D for because parent table column B needs more length as it stores names. when i add rows for nested table, the cells are coming merged in the output but i'm able to store data in the cells that are merged automatically when it gets inserted. in the output it comes as merged. so, i thought unmerge the rows once new are inserted. thats when i encountered the mentioned error.