Is this a plugin or theme problem?

Hard to say, for some reason file is not submitted. It could be cause by multiple same inputs in form.
Identification of problem needs more time and effort, I would say problem is with placing it in profile form.

Can you please tell me if it is worth waiting for this reason to be fixed in the next version of the plugin?
and the second question, do you need ftp access?

I have not told it is plugin issue.
We do not plan to invest time there as this feature is included in core already

How much will your help cost?

I found the reason. downloaded the old plugin avatar_free and in the plugin settings it was written to add to the <form> field

next post
name = "profile" enctype = "multipart / form-data"

the problem disappeared, thanks for your time

Yes that could be reason why $_FILES variable was empty