Macro Causing Custom Function To Fire

I have a large file, part of which amongst other things calculates life expectancy from a range of q(x) values (proportion of people that die moving from age (x) to (x+1). Life expectancy is calculated using a user-defined function (below).

My problem is that whenever I run a macro that changes the file, even parts of the file that don't affect the cells using the life function, it jumps into the life function. (An example: copying and pasting values on a different sheet). This is a hassle when stepping through other macros using F8, not to mention the time cost.

Some further possibly necessary information: one macro uses the GoalSeek application to set the target cell that contains the life function

By the way, this didn't use to happen in older versions of a similar file. When running the GoalSeek macro to change target life expectancy it did, but not for any other macro.

Here is the function:


Function life(data As Range)

' Aims to calculate Life expectancy from Qx values
' It assumes first value of Q is Qb, then Q0 to Qmax

Dim Nobs As Integer
Dim j As Integer, i As Integer
Dim q() As Double
Dim L() As Double
Dim T As Double, le As Double

Nobs = data.Rows.Count