Do you have the pivot table on the same sheet as the source data or on a separate tab?
Some of your conditional formatting might now be referencing pivot table cells if you have used absolute cell references and then inserted rows/columns to insert the pivot.
Always easier to check if you separate the original source data and the views of the data (here's a tab with conditional formatting applied, here's the tab with the pivot table) into separate tabs.
Do you have the pivot table on the same sheet as the source data or on a separate tab?
Some of your conditional formatting might now be referencing pivot table cells if you have used absolute cell references and then inserted rows/columns to insert the pivot.
Always easier to check if you separate the original source data and the views of the data (here's a tab with conditional formatting applied, here's the tab with the pivot table) into separate tabs.