After updating to Forms 2.4.2 - emails are not sending

Hi Balbooa,
On multiple sites (maybe all), after upgrading to 2.4.2, no emails are being sent.
I've unchecked all the minification settings and refreshed. After some experimentation, the issues appears to be: Performance -> minify -> Javascript

When this setting is checked no emails are sent.

I have the Form custom message enabled on most of my sites. I did notice, when the send button is pressed the "working" arrow icon is shown, but the customer message is never displayed and no email received.

I've tried this on several sites, the results are the same.

Could you please take a look.

Thanks
Marc