“[email protected]” email address being auto-filled

(Thank you to all in advance!!!) SOMETIMES, in CleanTalk’s Anti-Spam Log, the email address for the Sender of an email is auto-filled (somewhere along the line) with “[email protected].” This comes up as the address for replies. Soooo, if I’m not paying close attention (!), and try to Reply to an email, the return address I’m responding to is [email protected]–instead of the person’s actual email address, which might be [email protected], say. And the reply fails, of course. But at other times, the reply address is legitimate. That is, the email address supplied in the Email Address field and the email address supplied in Confirmation Email address field match.
The “origin” for these emails is WP Mail SMTP/wpforms. I ask for an email address, of course, and a confirmation of the email address–both of which are required, as the person fills in the form on my website.

So I don’t know where or how the client@gmail address gets added to CleanTalk. OH…. The program has run fine, without this problem, for 1-2 years. But recently–say, over the past 6 months–this problem has arisen several times (maybe, 5-6 times?!?!). But I also get clean, clear, proper notices in the CleanTalk Anti-Spam Log.
I hope this is clear. I’m sure someone–far smarter than I and well-versed in CleanTalk–will have a solution. Gracias!!!!!