There is a version that gets created when the content fragment is edited. The OOTB functionality of the content fragment is to support concurrent changes by multiple users simultaneously so that they do not overwrite each other's changes.
Basically the cookies are set which determine the start and stop of the current session. If you fall in the duration of the session at the time of clicking the cancel button. The content fragment is pointed to one version back, and that's the reason you are not able to see the updated value.
Note:- You can try changing the period autosave property as well to prevent the data loss if you want to increase or decrease the duration of the autosave.
@shaileshb584084 For which version of AEM are you facing this behaviour? I tried on AEM 6.5.0 and could not reproduce. Can you please open a support ticket for this so that this can be further looked into.