I just undone the activities. But now I’m back with my original problem. I guess I’ll do another post about it.
Still would be nice to have an answer to the above.
There is no command to cancel approval / unapprove for translations that match the source text. You can unapprove such strings in two ways:
You can do UNDO the action on the Activity tab, which you have actually already done;
You can filter such strings in the Editor via Advanced Filter → Translations field → select Same as source string. Do it in the Side-by-Side view because here you can select all filtered string and mass remove approvals for them