@ron,
Thank you for your query.
We were able to observe the issue but we need to look into it more. We have logged the issue in our database for investigation and for a fix. Once, we will have some news for you, we will update you in this topic.
This issue has been logged as
CELLSNET-47084 – Error when whole column is referred in ConvertA1FormulaToR1C1
@ron,
For your case, please use Cell.R1C1Formula instead to get the R1C1 formula for those cells.
Methods CellsHelper.ConvertA1FormulaToR1C1 and ConvertR1C1FormulaToA1 can only process some simple formulas. To support all complicated formulas, we need global models such as Workbook/Worksheet. So we may consider to make those two methods obsolete later and investigate whether we can provide similar APIs at the level of Workbook or Worksheet, or require users to set and get formula on the based cell directly.