Saving connection configuration violates a unique constraint

[instantiator]

On saving RoboConfig from the connection page, a unique constraint is violated in the db.

VectorPlus.Web.Service.VectorPlusBackgroundService.StoreRoboConfig(RoboConfig config) in VectorPlusBackgroundService.cs
+
db.SaveChanges();
VectorPlus.Web.Service.VectorPlusBackgroundService.SetRoboConfigAsync(string robotName, string robotSerial, string email, string password, string ipOverride) in VectorPlusBackgroundService.cs
+
StoreRoboConfig(roboConfig); // store final version with cert and guid
VectorPlus.Web.Controllers.ConnectionController.UpdateAsync(ConnectionViewModel model) in ConnectionController.cs
+
var response = await service.SetRoboConfigAsync(
Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor+TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
System.Runtime.CompilerServices.ValueTaskAwaiter<TResult>.GetResult()

NB. The RoboConfig should be a singleton in the database. This should be fixable by first searching for and removing any existing RoboConfig entries before saving the new one.

To be confirmed: I had believed this was already happening.

The issue could relate to a recent change that switches from creating a database context for each operation, to retaining a long-lived singleton database context.

If that's the case, the issue may be that transaction management needs to be implemented, so that operations can be flushed to the database in order.