[BUG] date (format) not properly read / written

[Brilator]

Popped up while using ARCitect and copy-pasting a date from another excel file to the isa.investigation.xlsx of a new ARC.
When the date format is changed (via Excel) the out format can be messed up.

#r "nuget:FsSpreadsheet.ExcelIO"

open FsSpreadsheet
open FsSpreadsheet.ExcelIO

FsWorkbook.fromXlsxFile("isa.investigation.xlsx").ToFile("out.xlsx")

[HLWeil]

What format was the input value in? (e.g. DD/MM/YY)

What was the error with the output? Was it not a date anymore, just a different format or a wrong date?