It's important to know which end is breaking. If, at the bottom end, the grommet has a rough edge or a ridge, that would tend to cut through the string with application of tension. Inspect thoroughly, then use nail file or sandpaper or whatever else the Harplisters suggest. If breaks are at top, I don't think the problem is the tuning pin, which almost never develops rough spots. Check the bridge pin for roughness or out of shape.
Remedy here is also to smooth it.
Since you have a Troubadour IV, I don't think the neck could be twisted far enough to make the string catch the bridge pin on an edge, but you might look to the string taking a straight vertical path from tuning pin, past the bridge pin past the lever and down to the grommet.