After update to SDK v4.0 I've faced a problem when data sent to the phone via DataLogging are getting lost.
Getting obtained only few data batches from many and sessionDidFinish method of Data Logging delegate doesn’t fire. The same trouble with DataLogging occurs with apps of other developers and Pebble 1 watches.
(iPhone 6 Plus, iOS 9.3.5; Pebble 1, Firmware v3.12.2)
Pebble team confirmed bug from their side.