Considering the 5.3 patch notes talk about changes to spiritbond & durability I'd say the no loss of durability change was intended.

https://eu.finalfantasyxiv.com/lodes...93f6c354e4dc8e

Changes to durability and spiritbond gain are processed after completion of a duty.

* With the exception of treasure dungeons and FATEs, gear will not lose durability nor will it gain spiritbond when a duty is failed.
* This adjustment will not affect durability lost upon incapacitation.
* Enemies defeated in the open world (leves, etc.) will no longer affect spiritbond gain.

Even though that last line does not mention durability, the fact that the prior notes talk about both spiritbond & durability... makes me believe durability is being treated the same for open world content: ie no loss of durability, along with no gain in spiritbond.