If your sample length is exactly 1/4, then it does indeed do that. The next update will make it so that the "experimental" algorithm automatically attempts to stretch it correctly, but for now I have 2 suggestions:
- Set a stretch of ~111%. This would make it sound okay in most cases.
- Instead of making your kick at exactly 1/4 length, why not make it a bit longer? This will give the algorithm more data to work with, plus you get the additional tail end to do more creative stuff with later on. (Say, if you wanted to have the tail last for longer than a beat, for example.)
Personally I always recommend the 2nd option over the 1st. Giving the algorithm more data to work with is generally considered a lot better than artificially stretching it.