Thank you for your post.
I am unable to replicate the issue. This is what I have done:
1. In FileMaker Pro 16 under macOS Sierra 10.12.5, I created a database file with the following tables and fields:
ID (Number - Auto-enter serial)
First Name (Text)
Last Name (Text)
2. The Relationships graph links Table::ID to Friends::ID
3. In the Friends table, I created the following records:
ID - First Name - Last Name
1 - Amy - Arnold
1 - Betty - Boop
1 - Connie - Conrad
1 - Debbie - Davis
1 - Erica - Ervin
4. In the Table table, I created one record with ID=1 and Name="TSGal"
5. In Layout mode, I formatted the Checkbox field to be a Checkbox Set, using values from fields "Friends::First Name" and "Friends::Last Name", including only related values from "Table" and showing values only from second field.
6. In Browse mode, in the Checkbox field, I selected "Boop" and "Davis".
7. I turned on Network Sharing and WebDirect access.
8. I turned off File Options Log in, and I assigned a password "admin" to the Admin account.
9. I uploaded the file to FileMaker Server 16, and opened the hosted file via FileMaker Pro 16. The Checkbox field appears as expected.
10. I launched Chrome and opened the hosted file via WebDirect. The Checkbox field appears as expected.
Let me know what I am doing differently than you so I can try to replicate the issue.
I created a new test file like yours and it works as expected- just like you demonstrate. I then looked at what may be different fin my real database and the test file. The only thing I see is that the field shown in the value list is a calculation field (name first & " " & name last)
But I tried that in the test file, and it still works. So, at this point I can't replicate the issue.
There are some differences in my real file and the test file, for example, the valuelist comes from a join table, but That in and of itself doesn't seem to me to be a cause. I'll keep trying to replicate the issue.