Hello!
I've bought TTGO OLED board. This one:
https://www.ebay.com/itm/ESP32-OLED-V2-0-Development-Board-240MHz-WiFi-Wireless-Bluetooth-Antenna-Module/402485554262?epid=17041625287&hash=item5db6022c56:g:MHcAAOSwPE5dmtds
And this SSD1306 display does not display every second line of the first 20 lines. The rest lines 21 to 63 display shows just fine.
I could not found a solution for this issue. Or is the display simply broken? 
Display test code:
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
void setup() {
Serial.begin(115200);
Wire.begin(4, 15);
pinMode(16,OUTPUT);
digitalWrite(16, LOW); // set GPIO16 low to reset OLED
delay(50);
digitalWrite(16, HIGH); // while OLED is running, must set GPIO16 in high
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C, false, false)) {
Serial.println(F("SSD1306 allocation failed"));
for(;;);
}
Serial.println(F("Success"));
display.fillScreen(WHITE);
display.display();
delay(2500);
display.clearDisplay();
display.setTextColor(SSD1306_WHITE);
display.setTextSize(1);
for (int y=0;y< 63;y++) {
display.clearDisplay();
display.drawFastHLine(0, y, 80, WHITE);
display.setCursor(50, 40);
display.println(y);
display.display();
delay(500);
}
}
void loop() {
}
