Exploring locations such as ruined towers, old battlefields or abandoned villages (locations where you mash 'continue' for a random chance to get loot) removes rest bonuses (and actually counts as resting). This happens even if you explore the location only once (causing only 2 or 4 hours to pass), but even then it's a bug because rest bonuses last much longer than that.

 

Save file - https://drive.google.com/file/d/1buO_-P2NZyi95688r3rUvDvInBLnmze2/view?usp=sharing

 

Explore the location and notice how the rest bonus from Tikawara expires afterwards.

Although this removes the rest bonuses, it doesn't actually count as resting because it doesn't clear wounds.

Hello Insolentius,

 

Thank you for taking the time and informing us about loosing your rest bonus when exploring in the open world. I've gone ahead and added this issue into our data-base for our Devs to investigate.

 

Cheers.