I have had an untold number of coders and Microsoft experts look at this problem. There is nothing that can be done.
Program 1 cannot be changed as the job requires it and it will only automatically spit out into excel. Excel immediately breaks several numbers across the spreadsheet by turning them into dates. Nobody at Microsoft can get the sheets to revert back into the original data correctly. Nothing can be done to preemptively format excel not to fuck the dates.
The program generates a report for us once a month. It can be generated as an excel file or as another file type which we cannot use. When it generates the excel file it breaks a bunch of numbers that are used often and all throughout our data as excel thinks they are dates. When we try and reverse any of those numbers in all the many ways people have recommended the data never goes back all correctly. So I have to manually replace the data cell by cell afterwards.
We are unable to preemptively format any settings in excel to prevent this from happening.
There once was a beta version of excel that had the exact feature we need (excel leaves all data untouched unless told otherwise), but for some godforsaken reason Microsoft got rid of that setting.