true, originally that "fix" was based on a ''cataclysm method log'' but afteward a staff member have found some Wotlk logs which also shows it was 150% dmg during "Wotlk Retail" as well.
You can read the staff comment here:
https://www.warmane.com/bugtracker/report/100262
The log he showed is from "wotlk" because it shows "Explosive Trap Effect" instead of "Explosive Trap" spell as showed here on "Cataclysm log":
https://www.warmane.com/bugtracker/report/55233
(on wotlk the damage is from "Explosive Trap Effect" while on Cataclysm is named "Explosive Trap")