KOReader freezes on exit when launched with "no framework"

When launching KOReader in no-framework mode on my Kindle, I run into an issue when trying to exit: the device completely freezes. The only way I've been able to recover is by long-pressing the power button until the three-option power menu appears; otherwise, I can't restart it, i didn't try the 40 sec power botton long press.

However, I found a workaround: if I select the Sleep option from those three power menu options, it works. But after that, I have to press the power button 3 more times—the device turns on, shuts down normally (turns off), and then boots back up normally into the native UI.

**Is this a known issue, and is there a proper fix for it?**