Here’s what I can confirm I’ve seen:
If I open the Editor on my phone (I do this sometimes to make changes to an app quickly, by using “Desktop Site” in Chrome to load the Editor properly on my phone), the times are shown in 12hr format.
If I open my app on my device (same device, with app saved to homescreen), the app loads with 24hr times showing. I noticed this last week and was able to “fix” it by switching my device’s default language to English US (instead of English Canada).
Edit: this also resulted in the date format changing from DD/MM/YYYY to MM/DD/YYYY (Canadian to American?). Again though, prior to making the language change on my phone, the editor was in “US” format and my app was in “Canadian” format. Same device, same Chrome browser.