Last two words of a line concatenate - space disappears

[danielsnider]

Under very specific conditions (I'm worried about it happening often) the last two words on a line concatenate. The space between the last two words disappear when last word is exactly 4 characters long and is styled italic, and bold+italics styling must be somewhere on the line.

Example Input:

Example Output:

*__this__ is atest*

Notice the last space between "a test" disappeared.