Please go to Start menu > Settings > Update & Security > Windows Update, View update history, check the latest updates for Office installed on your machines.
If the updates installed recently are April 2021 updates for Office 2016, I would suggest you download and install the latest updates, such as June 2021 updates manually on test computers to check the version number in Control Panel.
For MSI versions of Office, sometimes the version numbers are different in Office and Contral Panel.
Here is a similar thread, "Version number displayed in control panel different than version number displayed in Project", you may refer to Ismet Kocaman's answer.
"Not all updates change the version number that is listed in the About Microsoft Program_Name dialog box. Therefore, you must verify the properties for the program's executable file."
Any updates, please let me know.
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