IBM Verse: delivery error for emails to notes addresses of other domains

We use IBM Verse at andorid. At one smartphone a user get delivery errors for emails to notes addresses of other domains like:

User Joe Doe/SALES/OTHER-DOMAIN (Joe Doe/SALES/OTHER-DOMAIN@our-lan.de) not listed in Domino Directory

The correct asddress is Joe Doe/SALES/OTHER-DOMAIN@OTHER-DOMAIN
If the user send an email to this address from the Notes client at the PC the email is delivered. The address is not saved at the address book.

The problem do NOT occur for all users of IBM Verse of our domain.
An other user does not have the problem. He has the same settings in IBM Verse and at the entires of the person document of the server address book are equal.

Used Software:
smartphone: IBM Verse 9.4.0.2, Android 6.0.1
Server: Domino & Traveler 9.0.1 FP5,

Subject: Look at the Recipient & SendTo fields

Not sure if this helps but I am seeing something similar but on Traveler 9.0.1.6.

If I check the Recipients & SendTo fields I see that there is a space before the address which has failed. So, “CN=D Porter/OU=Dept/O=Org” becomes " CN=D Porter/OU=Dept/O=Org" but the odd thing it’s not happening to all the addressees. Of course this could be user error so I want to do a bit more digging and testing.

Subject: no user error

I checked it with different addresses at the users smartphone. There are not add of spaces.