This has been happening to me for about six months. Ever since the new advertising (long video ads) was implemented.

This is on mobile (iPad) using current iPad software and current version of the KS app.

80% of the time the game crashes before it fully loads.
15% of the time it crashes immediately after you select a level and begin playing, causing you to lose supplies and any special ingredients.
5% of the time it allows you to play a full level. Then it crashes as the stars are being rewarded, which results in the level not counting. No increase in points, no moving forward.

I'd say that <1% of the time it allows you to complete a level and move on without crashing.

This mobile app is completely broken, and I think it is due to the advertising in the app.