I can't seem to get Gameshark to work for more than a few seconds at a time.
It's a single player environment, and the steps I do go as followed
1. I edit the config file so that enabled is true
2.I make absolutely sure to save the file
3. I restart Minecraft, start my singleplayer world, and type /gameshark reload
4. the gui pops up, and it shows a line pointing towards a boss/pokeloot/etc.
5. the lines disappear, and the gui says "searching" forever, even when standing next to something that should be setting it off
I've tried uninstalling then reinstalling gameshark, and deleting the config file to little to no success.
I do not have a crash report, and I'm unsure of anything I could send that would be helpful(sorry about that)

I have the same situation. Aditionaly when i made a single player world with cheats enabled it worked without issue but when you go LAN and enable cheats it get's the same issue as said above. It automatically rewrites the gameshark to not enabled in the gameshark.json from what i saw.