Core Data object deleting error

Question

I am testing my app with TestFlight - and i see two same crashes on different devices (iPhone 5S 8.3 and iPhone 6 9.2).

This crashes happened only one time on each device but i think that there is some problem. When i open "Open in project" - i don't see where exactly in my project this crash occurs. As i see - this happens when Core Data runs object delete method.

I use Core Data to store cache and each time i receive new data from server - i clear all core data entities one by one and then create new. This is my function to clear cache. (This code is used to have iOS 7 support)

.SOC-columns img {
    padding-left: 220px;
}