You need to report issues as soon as you notice them, otherwise I will never know!
Heading to catherby right now to see the problem
Edit: I've just fished an inventory and it banked fine, and also walked back and started fishing again fine
Could you let me know all of your settings exactly?
Edit2: I think I know what you mean, I got logged out when i was fishing for some reason? I'm not really sure how to counter this, I thought it was apart of runescapes detection system as it used to happen (not sure if it still does) at the fishing guild. It's 6:30 AM at the moment, I gotta head to sleep so unfortunately I can't push any type of update until tomorrow.
I was using mirror with OSBuddy and didn't even get warned about the 5 minute idle, but it could be this.