What I understand from your question is somehow template is not detecting changes or it maybe that you are not changing the correct index.

You can try these:

• check if you are changing the correct index of the array if yes then :

• try reassigning the same variable which generally triggers the change detection mechanism like this:

  this.negotiationRounds[roundIndex][1].quoteCoverageAssessments[quoteSupplierIndex] = {...assesment}

  or you can manually trigger the change detection mechanism by importing the changeDetectorRef and triggering the detectChanges method:

  this.changeDetectorRef.detectChanges();