Hi Gery_T,
As per your description, please don’t worry I help you to fix your sort of issue in Excel.
It seems issue related with only sort function in Excel. However you can use filter the content. May I know my understanding is correct? if so, based on my test result in Excel and it seem I cannot meet same behavior as like you described above. I can sort Excel data add even use custom sort function to sort data. See test image below for your reference:
Since you mentioned, even new created Excel file with small data and you meet same behavior, Please go to File > Options > Formulas and be sure the Calculation Options setting is Automatic. Then go to Sort&Filter button on the Home tab of the Ribbon and check the outcomes.
Also, please try to open your Excel insafe mode to check whether it related to add-ins:
to confirm whether this is a bug in a specific version, please provide us the version information. To check version: Open Excel>File>Account>Product Information and capture a full screenshot and share here (Please mask your private message for protecting your private message) and we will be tested on that version and verify the result with you.
Meanwhile, if you don’t mind and if it is convenient for you, could you please send me a copy of the document file to me so that I can look from my side, and I will check this behavior and help you to fix it or sort data from you and send a file back to you.
If there is confidential information, then you can send it to me in Private Message
I appreciate your understanding and stay safe!!
Best Regards
Waqas Muhammad