Sync workflow (business rule?) requiring a field that is not on business rule anymore

Hi,

I'm working with a client and receiving a frustrating error. We used to have this column cr149_toteutetaanprojektinav2 in use but have since deleted it from all forms, etc. though it still exists in dataverse. Recently not one of the entities allow saving themselves, as an error pops up that tells a "Sync workflow 'Eteneminen prosessivaiheissa 2-' terminated with error 'Attribute 'cr149_toteutetaanprojektinav2' cannot be NULL'" (Detailed error log down)

Some context:
- Quite a simple Model driven app based on dataverse
- Error arises in the production environment, not in development, even though we've done the imports several times

- There are Business rules, a business process flow and one process (workflow) in the solution

- The name of the Sync process flow in error looks like an old name of one business rule (I could be wrong), but the condition step seems to refer to the business process flow more

Questions:

- What is a Sync workflow?

- All rows of the entity have a value at the column in question (checked this), so they should not be NULL in the data, where then?
- Might it help if we delete the whole column, or is there a risk that the error becomes unsolvable?

- Has microsoft recently done some changes to the business rules or business process flows? I e.g. see many more red mandatory -stars next to fields in my form than before. Wondering what's been happening behind the scenes.

- Could changing the scope of business rules have an effect? Currently most are at scope: entity

- Is this the right forum for model driven app questions?

ERROR LOG, with some attributes hidden

Exception Message: Attribute 'cr149_toteutetaanprojektinav2' cannot be NULL

ErrorCode: -2147220891
HexErrorCode: 0x80040265

ErrorDetails:
    ApiExceptionSourceKey: Plugin/Microsoft.Crm.ObjectModel.SyncWorkflowExecutionPlugin
    ApiStepKey: XX
    ApiDepthKey: 1
    ApiActivityIdKey: XX
    ApiPluginSolutionNameKey: System
    ApiStepSolutionNameKey: System
    ApiExceptionCategory: ClientError
    ApiExceptionMessageName: IsvAborted
    ApiExceptionHttpStatusCode: 400
    OperationStatus: 0
    SubErrorCode: -2146233088
    Plugin:
        PluginTrace: [Microsoft.Crm.ObjectModel: Microsoft.Crm.ObjectModel.SyncWorkflowExecutionPlugin]
[XX]
Starting sync workflow 'Eteneminen prosessivaiheissa 2-', Id: XX
Entering ConditionStep1_step:
Entering SetFieldRequiredLevelStep1_step:
Sync workflow 'Eteneminen prosessivaiheissa 2-' terminated with error 'Attribute 'cr149_toteutetaanprojektinav2' cannot be NULL'

TraceText:
    [Microsoft.Crm.ObjectModel: Microsoft.Crm.ObjectModel.SyncWorkflowExecutionPlugin]
    [XX ]
    Starting sync workflow 'Eteneminen prosessivaiheissa 2-', Id: XX
    Entering ConditionStep1_step:
    Entering SetFieldRequiredLevelStep1_step:
    Sync workflow 'Eteneminen prosessivaiheissa 2-' terminated with error 'Attribute 'cr149_toteutetaanprojektinav2' cannot be NULL'

Categories:

General Questions