Our current system of feature-flagging and a/b testing relies on the last digits of a UUID that is generated upon first launch of the app. (i.e. We rely on the UUID to be a random number, with a "granularity" of 1 in the last digit, so that we can take a modulo with another number for a/b/c/... testing)
HOWEVER: it turns out that the UUIDs that are generated in the field seem to have a granularity of 4, which breaks any feature flag that relies on modulo <=4.
It's better to switch to a simple pseudorandom number generated upon first launch, and use that for feature flagging.