I am finding that when I try to create the first record in a child table via a relationship, it doesn't work (101 record is missing).  But if there is at least one record in the child table, things work as advertised.  Do others have this experience?  Is it a "feature"?  Any way to get around it other than to just add a dummy record to the child?  TIA

This has not been my experience at all.  If you open the attached file and type into the portal's top row, does this work for you?

You will need to provide us more information to help us pin down why it does not work for you.  How are you related?  How are you attempting to create the new child record?  If via script, please post the script.  We can help you figure it out!

AllowCreation.fmp12

I have experienced this as well. In my current project, I create most records via what some call a MagicKey (create a record through an empty global into a related table). For this to work "create record via relationship" must be enabled in the relationship diagram.

An empty table will not allow me to create a record that way. Once a record exists, subsequent records are created without issue. I haven't troubleshooted it to any extend as yet as I haven't had time yet. But I found it happens when I trigger record creation via a UI button, which then invokes a script. It's possibly (thinking a bit more about it) that I'm using the wrong (related) field to trigger the creation of a new record as this is not always a problem. Can't test at the moment as the FMS is busy doing a big import. But this particular import also makes use of the same technique and has no problem creating records even in an empty table.

Something to test (if using this same technique) is using a modifiable related field to create a new record.