Maybe the Hyperlink feature is disabled on your colleagues
Spreadsheet. Try this to see if it works:

From the Menu bar:
Select Tools -- Options

On the Options dialogue box, Select the Spellings Tab and click the
AutoCorrect Option button

On the AutoCorrect dialogue box, select the AutoFormat As You Type
tab and check all the boxes in that tab if they are unchecked.

Then see what happens. May close and re-open the spreadsheet