Firewall issue with Aliases / Ranges

[Stef]

Hi

I have a firewall rule which allows incomming mail from specific domains only.

The easy way I've added all relevant ip addresses,
first I tried adding a range 63.208.196.0 CIDR 24 which should be all ip addresses from 1 to 255

However when I do specify individual addresses it works fine, otherwise these ip's are blocked as show in the 3 images,

Alias is an overview of all ip's in the range.

Disallow is specified in /24 range but not specifically
Allow is specified specifically

Is this a bug or am I doing something by specifying the /24 range ?

Thx