Changes in Power Apps not syncing in Sharepoint List

Question

Hi, I'm doing a project on my team wherein I needed to reflect a few additional details from a list item in Sharepoint 'Dashboard' to Sharepoint 'Masterfile' List. I managed to do this on our new Dashboard and Masterfile lists but this details should also be reflecting on our 'old' lists.

So I did the same changes in our old lists by making adjustments via PowerApps. I updated the edit form of our old Masterfile list, adding a choice and lookup formulas to be able to auto populate a field (Sub-channel) while still in the edit form. A specific sub-channel will appear when a req ID is selected manually by the team. 

After saving, we would see that the Sub-Channel is already filled out in the list item without manually entering in the edit form since we utilized a formula to auto-populate it. This would prompt to lookup values as well for Final Sales Org, Channel and Customer as they are addt. lookup columns from Sub-Channel.

Unfortunately, since the adjustment is recent this auto-populated formula is not syncing in the already created list items unless we go back in the edit form click save to reflect the highlighted fields here.

Is there anyone know any causes, workarounds or solutions perhaps? I think this might be some syncing issues but I would not want to go in the edit form for each list item just to successfully reflect these details in the list since we're updating both 2024-2025 items that would be a tedious process.