Error in Jlex avatar

Hi,
i've just updated my website to joomla v4 and almost everything is working well.
one problem that i have is with CB avatar used in jlex comment.
I have an error:
Call to a member function avatarFilePath() on null

I asked to jlex comment developer and they said:

it's related to the "Community Builder" extension. It seems they updated their framework so the old functions might be outdated and not working. Could you help me ask their team if this function still works?
$thumb = CBuser::getInstance($userid)->avatarFilePath();

Could you help me please?
Thanks

That API has been deprecated for a few years now since CB 1.9. The function still exists, but it might not work with newer avatar field features. The correct way to get the avatar field is the same way all fields are obtained via the getField API below.

www.joomlapolis.com/documentation/127-community-builder/279-tutorials/18361-obtaining-field-values-through-getfields-api

However that's not their issue. CBuser::getInstance will return NULL if the $userid doesn't exist. There's a second parameter on that function that can be set to false so it never returns NULL otherwise they need to check for NULL before calling avatarFilePath (or ideally getField).

Thanks a lot,
 i will forward your answer and see what they can do.