Describe the issue

Certain combinations of CSS rules applied to decorations can cause the caret to consistently jump to the end of the current line on Arrow Down instead of navigating down to the next line:

I assume that this is related to how this decoration changes the height of the line. But it's not as simple as that because not all height-changing decorations reproduce the issue.

For example, the following CSS reproduces the bug:

.decoration {
  border-bottom: 0.3em solid gray;
  font-size: 2em;
}

However, this CSS does not, despite being almost the same:

.decoration {
  border-bottom: 0.25em solid gray;
  font-size: 2em;
}

And it's not just a height threshold, because this CSS also does not reproduce it despite being taller:

.decoration {
  font-size: 3em;
}

This decoration is applied using a StateField as required.

Browser and platform

Chrome 139 on MacOS Sequoia 15.6.1

Reproduction link

https://codesandbox.io/p/sandbox/jz93dp