I'm having trouble with a nested if returning false in only certain conditions

I am creating column collapsing application and I am having trouble with a certain formula changing its heading to false when it should be showing a value.

=IF($CE2="Line 3",IF((COUNTIF($BY:$BY,">0")>0),"Line 4",IF((COUNTIF($BZ:$BZ,">0")>0),"Line 5",IF((COUNTIF($CA:$CA,">0")>0),"Line 6"))),IF($CE2="Line 4",IF((COUNTIF($BZ:$BZ,">0")>0),"Line 5",IF($CE2="Line 5",IF((COUNTIF($CA:$CA,">0")>0),"Line 6"," ")))

In all of the arrangements of selected "lines", it shows the proper value except when Its column is the last in the series, the rest continue to work properly.

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