Objective-C dot accessor behaves differently with implicit getter

Can one of you kind people please help me to understand why I get '(null)' for the second line in the output but not the fourth? Many thanks in advance

MyClass.h

@interface MyClass : NSObject
@property (readonly) NSString *foo;
@property (getter=getBar, readonly) NSString *bar;
@end

main.m

@implementation MyClass
- (NSString *)getFoo { return @"foo"; }
- (NSString *)getBar { return @"bar"; }
@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {     
        MyClass *myClassInstance = [MyClass new];

        NSLog(@"%@", myClassInstance.getFoo);
        NSLog(@"%@", myClassInstance.foo);

        NSLog(@"%@", myClassInstance.getBar);
        NSLog(@"%@", myClassInstance.bar);
    }
    return 0;

output

foo
(null)
bar
bar