slides from Google – RAND () causes a calculation error in "Link to sheets"

= IF ($ AI $ 2 <> "", AH34, $ AJ $ 2 + ($ AK $ 2- $ AJ $ 2) * rand ())

That formula is used to freeze the value of rand ().

I am able to "Link to spreadsheets" in Google Docs / Google Slides, but just after the copy, asked for "Update". I clicked "Update" and it shows a different value.