Can't modify Mails On Event recievers of some Element Updated type

Greetings to all and thanks in advance for your time.
I'm trying to change the recievers of some events in the "Mails on Events" section, but I haven't succeded with the "Action" type of "Event Updated".
If I want to modify an existing one, at the moment I push the Save button it shows an error that says "Invalid controls. the field 'element' is mandatory". The "updated element" field is empty, but I can´t modify it.
If I want to create a new event, in the "event update" field, doesn´t show the "Action" type.
I wanted to know if this is an error in my procedure, a limitation of this version or a bug of some type.
By the way, I'm using Projeqtor 8.3.2 with Chrome 83 (Official Build).
Kind regards.