You're not the only one having this trouble, but i thought it was just me, the Client seems to want to do what i call "Mini" freezes when i do things, like fishing, it has like Pauses, it freezes my mouse and computer time to time, nothing too major, I just thought again it being myself. The issue doesn't happen a lot, but ya, i've had it freeze up my Opera Browser before, but no crashing, I know with some clients if you leave them up for long periods, depending on conditions, they start to wig out as I would say. Hopefully that issue will go away in due time.
If you could try clearing your Cache, if they had it build into the Client would be a lot easier, Normally there is a "Clean or Clear Cache button" for most Clients. Than again with your computer going into sleep mode can cause issues with some stuff if you have Windows it its bad for things like that, I've turned off Auto sleep because of issues like that. Look into that first. Sleep mode to wake mode might be a wig out for the client and computer i have this issue with my TV when i Switch HDMI to my PS4 and back and forget my client is up . Weird issues happen at times. Like does your client play normal before Computer goes into sleep mode?
P.S I would try also restarting your Computer time to time, as well. These might not fix the issue, but Windows is known to have issues with sleep mode, Windows tends to break things at times wit updates and small things. I don't think its all the client issue though. With it freezing your Whole system freezing and crashing your client, i'd say more likely Sleep mode is your issue. Sorry if i was repeating a bit, just running down a list of Possibilities.
