Why does the text disappear on the display?

Question

Arduino

To work with the screen, I use the OLED_I2C library.
The program embedded in the Arduino Uno began to grow, and after creating an array in one of the classes, I noticed that part of the text on the screen had disappeared.
If you remove one class, then one line will appear.
For some reason, the second one did not appear, although in the photo where the text is cut off there is a question mark (end of the second line)
What could be the reason for this? Not enough Arduino resources?