Form field not populating data from from existing db record in "update / edit records" modal

I have an “update records” form (inside a modal) that doesn’t populate a specific field when the “Update” button is clicked. The modal pops up, the form displays and it even populates one of the fields from the database. But the other field in the form is blank.

It allows me to enter new data into the blank field and it even updates the database but for some reason, I just can’t get the existing data from the db to show in the field when the modal is called.

This is for an image gallery I built based on this tutorial from @ben :
https://youtu.be/o_rZmbZyS14

In this screenshot you can see the “Edit Gallery Details” button and the “test description” data in the “Gallery Description” field in the table above the button.

Screen Shot 2020-01-26 at 11.49.08 AM1533×793 65.3 KB

When I click the “Edit Gallery Details” button, I get this modal pop up. Name of gallery is shown correctly.
The description field is blank (not shown in this screenshot) but it allows me to add a new description in the blank field (I typed “Revised Description” in this screenshot).

Screen Shot 2020-01-26 at 11.51.59 AM1668×767 43.2 KB

After updating the data, it shows my updates in the table and they appear to be valid.

Screen Shot 2020-01-26 at 11.52.09 AM783×669 39.3 KB

Here is my app structure.

image-screen-updateform1056×1536 138 KB

Here is my code.

Screen Shot 2020-01-26 at 12.04.02 PM2933×2315 903 KB

Any ideas?
Thank you in advance.

Edit: added @ben for tutorial video credit.