Can there be difficulties or unexpected behaviors if one of the class's closures accesses its methods or properties?

Yes, when closures are used inside a class to access its methods or properties, there can be issues related to capturing self and potential retain cycles.

If a closure captures self without using a weak or unowned reference ([weak self] or [unowned self]), it can prevent the instance of the class from being deallocated because the closure holds a strong reference to self, and self may hold a reference to the closure.

Example of the problem:

class MyClass {
    var closure: (() -> Void)?
    var value = 10

    func setupClosure() {
        closure = {
            print(self.value) // capturing self
        }
    }

    deinit {
        print("MyClass deinitialized")
    }
}

var obj: MyClass? = MyClass()
obj?.setupClosure()
obj = nil // MyClass will not be deallocated due to retain cycle

To avoid this, a weak reference is used:

closure = { [weak self] in
    guard let self = self else { return }
    print(self.value)
}

Thus, it is important to carefully manage capturing self in closures within classes to prevent memory leaks and unexpected behaviors.