After my first three encounters, I started putting #WhatInGrabsNameIsThis hashtag in edit summary whenever I have to revert or fix bad armchair edits done by Grab team.
If you are also doing this, I encourage you to do the same.
Statistics of recent changesets with #WhatInGrabsNameIsThis in edit summary could be viewed on Pascal Neis’ website.
Note: In case you are just pointing out their mistakes, using the hashtag in changeset discussion works too. (So they could be found by more specialized tools)