I spoke with someone about this at Aweber the other day and then worked with the Elementor team on it also and we have narrowed it down to a Multisite issue with the Aweber plugin.
On a Multisite in the Elementor builder, the Aweber element and the Aweber option in the form element (Elementor Pro) is not showing up.
It only happens on Multisite installations. See this screencast about it by the Elementor team: https://www.loom.com/share/b97082e82d1d4b5bbfdfe1dc350e7f82
and it seems to be an Aweber plugin issue not an Elementor issue though they are continuing to investigate.
I have reported it on the VIP help line also