In free jqGrid v4.14 a change was introduced in order to let the getRowData() function take the values of cell editing into account.

Unfourtunately this change is breaking when one uses the editable property in the colModel as a function (ref: https://github.com/free-jqgrid/jqGrid/wiki/editable-property-of-colModel-as-function).

Basically as soon as we attempt to save a row, we encounter a stack overflow in JavaScript. This stack overflow did not exist with an earlier version of free jqGrid.

Simple example which reproduces the bug:
https://jsfiddle.net/kmoens/j28uoo44/6/

The same example, but with free jqGrid v4.13.6
https://jsfiddle.net/kmoens/j4ney3us/