### Godot version

v4.2.dev5.official [e3e2528ba]

### System information

Godot v4.2.dev5 - Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 970 (NVIDIA; 31.0.15.3623) - Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz (8 Threads)

### Issue description

#79975 closed his issue too early, it's a separate issue to #78434.

I'll just repost his same gif:
![256703477-a7db18c1-eccf-42af-85ef-1a1472f30c73](https://github.com/godotengine/godot/assets/15337628/1a7926ea-a9d8-4eb3-a857-8d34df23228f)

### Steps to reproduce

I had a theory it was related to editor settings and I tracked it down:

1. Editor -> `Display Scale` = Custom
2. Editor -> `Custom Display Scale` = 1.15
3. Click Save & Restart
4. Print stuff

```
var number := 0
func _process(delta: float) -> void:
	number += 1
	print(number)
```

The scale number matters, 1.1 seems to be fine but smaller decimal places such as 1.15 are what cause the issue.

### Minimal reproduction project

[printbug.zip](https://github.com/godotengine/godot/files/12683758/printbug.zip)

if ((int)p_frame->lines.size() - 1 <= p_frame->first_invalid_line) {
		p_frame->first_invalid_line = (int)p_frame->lines.size() - 1;
	}
}
void RichTextLabel::add_text(const String &p_text) {
	_stop_thread();
	MutexLock data_lock(data_mutex);
	if (current->type == ITEM_TABLE) {
		return; 
	}
	int pos = 0;
	while (pos < p_text.length()) {
		int end = p_text.find("\n", pos);
		String line;
		bool eol = false;
		if (end == -1) {
			end = p_text.length();
		} else {
			eol = true;
		}
		if (pos == 0 && end == p_text.length()) {
			line = p_text;
		} else {