We test every single pack before it ships to make sure it's in balance and has the proper IR on each cell. It's very unlikely you would get a pack with an issue. Once in awhile a pack may have an issue after a few runs and we do take care of these issues if it's a defect.

If the pack has swelled and all cells have swelled this isn't a defect this is the way the pack was used or misused. If one of the cells swells and the others are fine this is a defect with that cell and we do take care of that.

Swelling should not be confused with expansion. All Lithium cells expand under use. Since we are limited by the ROAR case size the factories are making maximum size cells to try and get the mAh and IR to be as good as possible. This means when the cells get used they will expand and push against the case and distort the case. This is normal and the only way we could keep this from happening would be to use smaller cells and leave a gap inside the case for expansion but this would sacrifice performance.