I'm using 4.3pre9, in the PHP mode using a double quoted string literal with an escaped double quote inside it stops the literal highlighting at the escaped double quote instead of ignoring i.
<?php echo "Foo\" Bar Foo"; ?>
The literal highlighting stops at \" and the mode tries to interpret and highlight Bar Foo as PHP statements.
It doesn't appear to be a problem in the mode file itself, as using the modefile from 4.3pre6 also shows the problem, while using 4.3pre6 itself does not.
I have not tried other modes to see if they are also affected.