XE7 and more With weirdness

100% reproducable fail: Access violation at address 00B5464D in module ‘MyApp.exe’. Read of address 00000040.

Fails:

    tpLot := Tp.Add;

    with tpLot do

    begin

      LotId := Lot.Id; // <–BANG

      LotNo := Lot.LotNumber;

      ExpiryDate := Lot.ExpireDate;

      ProducedDate := Lot.ProducedStartTime;

      ArticleId := ArtSum.ArticleId;

      ArticleNo := ArtSum.ArticleNumber;

      OriginalArticleId := ArtSum.ArticleId;

      Quantity := NumDPacks * ArtSum.BaseUnitsPerKPack;

      NetWeight := Quantity * ArtSum.NetWeightPrBaseUnit;

      GrossWeight := NetWeight +

        (ArtSum.TaraWeightPrFPack * Quantity);

      LotLockState := Lot.LockStateCode;

    end;

Works:

    tpLot := Tp.Add;

    tpLot.LotId := Lot.Id;

    tpLot.LotNo := Lot.LotNumber;

    tpLot.ExpiryDate := Lot.ExpireDate;

    tpLot.ProducedDate := Lot.ProducedStartTime;

    tpLot.ArticleId := ArtSum.ArticleId;

    tpLot.ArticleNo := ArtSum.ArticleNumber;

    tpLot.OriginalArticleId := ArtSum.ArticleId;

    tpLot.Quantity := NumDPacks * ArtSum.BaseUnitsPerKPack;

    tpLot.NetWeight := tpLot.Quantity * ArtSum.NetWeightPrBaseUnit;

    tpLot.GrossWeight := tpLot.NetWeight + (ArtSum.TaraWeightPrFPack * tpLot.Quantity);

    tpLot.LotLockState := Lot.LockStateCode;

Lot and ArtSum are properly initated and readable (inspected in debugger), so I assume it is the assignment that fails.

The problem is, I cannot reproduce in a mini-example.

If I wasn’t set at eradicating all with statements before, I surely am now.

#sigh