During development, generally your testers will be running a version of the game that could be a number of days old.
By the time you’ve got back bug reports there is likely to have been significant progress on the game since. There’s every chance during interim development that bugs could have been fixed before QA found them. Also, the goalposts could be moved; some aspect of the title may have been significantly changed and that bug report you got no longer makes any sense.
For these reasons it’s imperative that when you get back bugs, you know what version of the game they were running. There’s a number of ways you can address this: