If a member have pm labels with id>60 and try to assign that label to any message it shows labels_too_many error.
There is a code in PersonalMessage.php file
// Check that this string isn't going to be too large for the database.
if ($set > 60)
$updateErrors++;
I think, here should be something like this
// Check that this string isn't going to be too large for the database.
if ($smcFunc['strlen']($set) > 60)
$updateErrors++;
Is it fixed in 2.0.16?
Doubtful. It was a fairly large rewrite to fix in 2.1.
I'm testing this fix now.
Fix coming in 2.0.16.
Fixed in 2.0.16.