OCMock unpredictable value when testing class method parameter argument

I'm getting really unpredictable behaviour when trying to test a class method with OCMock. The problem I have is when trying to get the value of the parameter passed to the class method.

When I call the method on the mock inside my test everything works perfectly:

- (void)test {
    id mockArchiver = OCMClassMock([TestArchiver class]);
    [[mockArchiver class] archiveRootObject:@[@"1", @"2", @"3"]];
    OCMVerify([mockArchiver archiveRootObject:[self objectChecker]]);
}

- (OCMArg *)objectChecker {

    return [OCMArg checkWithBlock:^BOOL(id value) {
        // value is equal to correct array
        return YES;
    }];
}

However the problem comes when I call the method in the actual class I'm testing:

- (void)test {
    id mockArchiver = OCMClassMock([TestArchiver class]);
    Archive *archive = [[Archive alloc] initWithArchiver: mockArchiver];

    [archive useArchiver];

    OCMVerify([mockArchiver archiveRootObject:[self objectChecker]]);
}

- (OCMArg *)objectChecker {

    return [OCMArg checkWithBlock:^BOOL(id value) {
        // value returns very sporadic data
        return YES;
    }];
}

The useArchiver is very simple...

- (void)useArchiver {

    [[self.archiver class] archiveRootObject:@[@"1", @"2", @"3"]];
}

The value returned by value is very unpredictable. Sometimes it returns the correct object but most of the time it doesn't. Some example things it might return:

value   __NSCFString *  @"archiveRootObject:"   0x00007f80725f34f0

value   __NSCFString *  @"2015-02-02 10:22:47.838"  0x00007fda585e40d0

value   __NSArrayM *    @"1 object" 0x00007faa2158aaa0:
    [0] OCMBlockConstraint *    0x7fa420632340  0x00007fa420632340

value   __NSArrayI *    @"3 objects"    0x00007fed53da1c50: // correct returned object
    [0] __NSCFConstantString *  @"1"    0x000000010b78e920
    [1] __NSCFConstantString *  @"2"    0x000000010b78e940
    [2] __NSCFConstantString *  @"3"    0x000000010b78e960

Or a EXC_BAD_ACCESS on the line that returns the OCMArg block