_txtInfo = new Text(300, 56, 8, 150);
The textbox is 56 pixels high and placed with y-offset of 150.
Game resolution has 200 vertical pixels.
This leaves 50 pixels between 150 and 200, which means 6 full lines (48 pixels) and only 2 pixels from the 7th line.
That means the game currently supports only 6 lines of text.
The fact that the textbox is bigger is probably a bug, and the fact that on some scaling settings the 7th line is visible is a complete coincidence.
Summary: limit your text to 6 lines.