Hi @v-xida-msft,
Thanks for the info. I would very much agree with this statement:
"I think you have some misunderstand on the update mechanism within the Edit form of canvas app." 🙂 I'm still learning this and editing forms is definitely confusing me.
To answer your initial questions, the Description_1 field is a Choice type field in my SP list. It is pulling its data from an Excel table. So, in the Items field of the cboDescription_1 combo box, it just says Products which is the name of the Excel table. The combo box itself is setup as a Double layout so that it shows the Product Description and then shows the Part Number below it. To give a visual, here is what my screen looks like when blank:

The Base Product drop-down list in the upper, right-hand corner has the capability to control the first four combo boxes under the Description column. For simplicity, I am just focusing on the first one since the other three are behaving the same way but for the same reason. The DefaultSelectedItem field of the first combo box has a variable called varDescription_1. The Base Product drop-down box sets that variable based on what is selected.
I added some fields at the bottom for testing just so I could get a better understanding of what happens when I do certain things. I put labels above the fields so you can see what formula it is looking at. As the screenshot below shows, if I select an item from cboDescription_1, it populates to cboDescription_1.Selected.ProductDescription.

This works how I would expect and is used in the formula for the Next button which does a ClearCollect on everything in the form. Here is a sample for the code for just the first line:
ClearCollect(
colQuoteDetails,
{
Description: cboDescription_1.Selected.ProductDescription,
PartNumber: cboDescription_1.Selected.ProductPartNumber,
MSRP: txtMSRP_1.Text,
Qty: txtQty_1.Text,
PartnerDiscount: txtPartnerDiscount_1.Text,
RegistrationDiscount: txtRegistrationDiscount_1.Text,
UnitCost: txtUnitCost_1.Text,
TotalCost: txtTotalCost_1.Text
},
etc...
I send the collections to Flow and that all works fine for a new quote. When I edit a quote, the values get stored in the Card as opposed to the combo box (if that makes sense). Here is what the form looks like when I edit a quote:

You can see that cboDescription_1.Selected.ProductDescription is blank but crdDescription_1.Default has the value. The Update field of crdDescription is
{Value:cboDescription_1.Selected.ProductDescription}
So, both the info I send to Flow and the Update function rely on the data being in cboDescription_1.Selected.ProductDescription and that's what I can't figure out. Once I am editing a quote, I can't figure out how to get the value from crdDescription_1.Default to cboDescription_1.Selected.ProductDescription.
Hopefully my explanation makes sense. I'm still coming up to speed on some of the terminology.