Either revert the aggro AI/behaviour back to the original, or....

Drazomyst - Dreamweaver

....announce that the aggro behaviours have changed. It's not fun(ny) finding out the hard way. b:surrender

To those who haven't noticed yet, originally once the mob "gave up" aggroing (and gave a yellow glow as they retreated) they wouldn't re-aggro you again unless after they reached their destination and stopped glowing. Now, if you get in range of them again or attack or be aggro'd by another mob near them, they'll turn and aggro again even while they were still retreating. It might be more realistic and challenging now, but a simple notice about the change would've been nice.