E-mail notifications on resolved when resolved=custom status

[Jee]

Hello,

I have created a custom status X and defined issues to be resolved when they reach status X. I have configured users (reporters as well as viewers monitoring it) to receive e-mails for resolved issues, as well as for issues that reach status X, however the users do not receive e-mail notifications for resolved issues. They do receive notifications for all other configured status changes.
If I redefine resolved as another status than X (e.g. closed), the notifications for status X start arriving.

What setting do I need to set?

thanks in advance,

Jee