RestKit CoreData unrecognized selector sent to instance count

[southfox]

Hi,

I've found a lot of crashes pointing to some of mine NSManagedObject entities like Price

Fatal Exception: NSInvalidArgumentException
-[Price count]: unrecognized selector sent to instance 0x1c46868b0
_CF_forwarding_prep_0

Do you see [Price count]?, I don't use this line in any part of my code.

Another with my entity User:

Fatal Exception: NSInvalidArgumentException -[User count]: unrecognized selector sent to instance 0x1c46868b0 _CF_forwarding_prep_0

And with another entity: Location

Fatal Exception: NSInvalidArgumentException -[Location count]: unrecognized selector sent to instance 0x1c46868b0 _CF_forwarding_prep_0

Attached is the crash from Crashlytics:

com.xxx.xxx_issue_6226_crash_a673920aeace45a9add482642527ee39_18de8bc1bc4611e7bdd156847afe9799_0_v2.txt

I've found this links related to my crash:

https://stackoverflow.com/questions/28077521/coredata-setting-relationship-gives-error-weatherobservation-count-unrecogn
https://groups.google.com/forum/#!topic/restkit/rmL20pbK64I

The issue is: I cannot reproduce this, and tried several ways. And I don't where to look yet.
It happens in iOS 8, 9, 10, 11.
I'm using RestKit (0.27.2) + Core Data under Xcode 8.3.3.

Thanks.