2.5.0: WiFiUDP Broadcast using static IP & AsyncUDP Broadcast problem

[ErinQvnm]

Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: [ESP-12F | ESP12-S]
• Core Version: [2.5.0 Stable & Git 6c5269a]
• Development Env: [Arduino IDE]
• Operating System: [Windows]

Settings in IDE

• Module: [Generic ESP8266 Module | Nodemcu]
• Flash Mode: [dio]
• Flash Size: [4MB/1MB]
• lwip Variant: [v2 Lower Memory]
• Reset Method: [ck]
• Flash Frequency: [40Mhz]
• CPU Frequency: [80Mhz]
• Upload Using: [SERIAL]
• Upload Speed: [115200]

Problem Description

I'm using 2 ESPs as a server and a client. UDP broadcast didn't work when client using static IP. I tried using WiFiUDP library.
I also tried using me-no-dev AsyncUDP library. udp.broadcastTo() stopped working.
All the sketch below worked for core 2.4.2, after 2.5.0 they just doesn't work.

MCVE Sketch

###Using WiFiUDP library:
Server:

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>

IPAddress ip_ap(192, 168, 1, 123);
IPAddress gw_ap(192, 168, 1, 1);
IPAddress sn_ap(255, 255, 255, 0);
WiFiUDP udp;

void setup() {
	Serial1.begin(921600);
	WiFi.softAPConfig(ip_ap, gw_ap, sn_ap);
	WiFi.softAP("testtest", "testtest");
}

void loop() {
	delay(1000);
	udp.beginPacket(IPAddress(192, 168, 1, 255), 2424);
	udp.print("TEST TEST");
	udp.endPacket();
}

Client:

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>

IPAddress ip_sta;
WiFiUDP udp;

void setup() {
	Serial1.begin(921600);
	WiFi.begin("testtest", "testtest");
	while (WiFi.status() != WL_CONNECTED) {
		delay(1000);
		Serial1.print(".");
	}

	//Set client to static IP
	ip_sta = WiFi.localIP();
	ip_sta[3] = 115;
	WiFi.config(ip_sta, WiFi.gatewayIP(), WiFi.subnetMask()); //if comment this line code runs perfectly

	udp.begin(2424);
}

void loop() {
	int packetsize = udp.parsePacket();
	if (packetsize) {
		char packetBuffer[32];
		int len = udp.read(packetBuffer, 32);
		packetBuffer[31] = 0;
		Serial1.print("PACKET: "); Serial1.println(packetBuffer);
		Serial1.print("LENGTH: "); Serial1.println(len);
	}
}

###Using AsyncUDP library:

#include <ESP8266WiFi.h>
#include <ESPAsyncUDP.h>

IPAddress ip_ap(192, 168, 1, 123);
IPAddress gw_ap(192, 168, 1, 1);
IPAddress sn_ap(255, 255, 255, 0);
AsyncUDP udp;

void setup() {
	Serial1.begin(921600);
	WiFi.softAPConfig(ip_ap, gw_ap, sn_ap);
	WiFi.softAP("testtest", "testtest");
}

void loop() {
	delay(1000);
	udp.broadcastTo("Anyone here?", 2424);
	Serial1.println("LOOP");
}