I set the Options setting in Workbench to show 10 significant digits.

I restored the ANSYS_Issues.wbpz file in the zip file above and opened system D, clicked on the Acceleration load and scrolled to the end.

If you don't change the displayed digits, and copy cell then paste in matlab or excel, you only get the digits displayed. For example, with the default 5 significant digits displayed, the data look like this:

Performing numerical analysis on data that lacks the full precision could cause errors.

I took the last 194 rows of acceleration data and reassigned it a new time column starting at zero.
The statistics on that last 0.05 seconds of the 20 second history shows a 317 Hz frequency.

I don't know what your matlab code is doing.

Kind regards,