Very wild guess: they did test it and maybe even stress tested it... with the phones they had in their office. Out in the field people were using different phon

Very wild guess: they did test it and maybe even stress tested it... with the phones they had in their office. Out in the field people were using different phones with various versions of the mobile OS. Not sure if this is an Android or iOS app but either way, it's possible there was something quirky in the implementation that didn't show up on the test phones or simulator. They may have even made a poor assumption such as there always being a network connection. That would be the case in their office but not guaranteed out in rural areas especially in rural areas with a sudden convergence of lots of people with cell phones in a confined space that doesn't usually have that much device density.