I’ve noticed the same exact pattern. They work just fine, at first... but after about a week or 2, that’s when the trouble begins.
Something else I’ve noticed, is when my PC has been powered down for a long period of time (for example overnight) and I power it up for the first time of the day, then that’s usually when I notice any issues. Yet, it does seem to be random.
I wonder if there is a conflict withing Synapse 3, regarding the devices’ profiles. I randomly get duplicate profiles being generated. Everytime I try to delete them, they tend to keep coming back. The sync features doesn’t seem to work that well either.
Same thing here with my naga v2 pro, dead but it comes back randomly but won’t hold charge anymore...