Why does Entity Framework keep setting these properties to their default values? - asp.net-core

Question

Ecommerce web site, written using ASP.NET Core 3.1, Razor pages, EF 3.1.8 code first.
I have a model called Globals. When I first set this up, I included the default values for four of these (other properties not shown for clarity)...
[Column(TypeName = "decimal(18,2)")]
public decimal DeliveryCharge { get; set; } = 3.5M;
[Column(TypeName = "decimal(18,2)")]
public decimal FreeDeliveryOver { get; set; } = 70.0M;
public string StripePublicKey { get; set; } = "pk_test_...";
public string StripeSecretKey { get; set; } = "sk_test_...";
When I deployed the site to the production server, I manually set the two Stripe keys to the live values, so the site could take payment.
This all worked fine until one day, seemingly out of the blue, we got an exception from Stripe, as the site was using the test keys again. I checked the Globals table, and yes, the test keys were back in there.
Now there are only two of us developing this site, no-one else has access to it, so no-one has done this manually.
Baffled, I set them to the live values, somewhat worried about how this could have happened.
A week later, it happened again. A this point, it dawned on me that as the only place in the entire code base that had the test keys was this model, and the migrations that were generated, maybe EF was resetting the default values. I have no idea why this would be, as I would have thought that these values would only have bene used when the table was created, or these properties modified.
However, I removed them from the model, hoping that this would solve the problem.
Thankfully, the values on the live site have not been changed again, but I just ran the project in Visual Studio, and got an error as the Stripe keys in my local Globals table were null, presumably as I had removed the default values.
The odd thing is that the two decimal properties in there did not have their values reset to the defaults. I know this, as the FreeDeliveryOver one was changed to 50.0M shortly after we launched.
Anyone any idea what's going on here? I'm now worried that the live site is going to have the keys set to null, breaking the site when I'm not looking.

Answer 1

Is there any part of the app where you seed initial data?
Try to search the db table's entity name, to see if there is any programatic initalization.
Since the entity's default constructor would assign the values, is there any place where a new instance of this class is created? if so, you might have code where a new instance is returned with the default values, and later maybe attached and saved to the context by accident.
Does "globals" have row id's? are you referencing the same id when working with them and load them in the context?
( i will delete if non of the above is the case... )
After reading again the part where the decimals have stayed in place, is there any part where you update the values, but dont assign the string fields correctly? Dont forget that an update will go over the whole object, if its just .Update(data);