When sorting a block of cells any defined functions in cells in the sort area are replaced with static values.  I selected the unspecified version since the version I'm using, 2.4.3, was not available for selection.  

Reproducible: Always

Steps to Reproduce:
1. Create a set of data based on functions
2. Sort the data according to the cells with the function definition
3. Check if the function still exists in the cells that originally had functions
Actual Results:  
All function definitions are replaced with static values.

Expected Results:  
The function definitions should remain so that further dynamic calculations can take place for future sorts.

I didn't mark this as critical because a workaround is to copy the function into a non-sorted cell and then overwrite the affected cells with this temporary save of the function.  Otherwise, I would consider this a loss of data in the form of the functions that one may have developed but no longer has access to without restoring a save or backup.