A bad battery could be a cause for crash. I bought 3 Breezes, out of the included 6 batteries, one of them drained very fast from around 50%. I just didn't use it anymore.
Was it the first time you used that battery? The 60% that you quoted might mislead. If the battery survived the crash, I don't know how to test it without a Breeze.
Normally, when WiFi signal is lost, the Breeze would wait about 1 minute then fly up to preset altitude then return home. If the battery runs down at any point during RTH course, it would drop to crash.
Once in a while, I just hovered the Breeze to test the battery for how it drained.