Hello Alex,
Yes, I have something similar – but I think it's the Flic Hub losing connectivity, not the Philips Hue connection per se. My Flic is on Wifi and I think, for some reason, the DHCP lease doesn't renew properly, cutting off Flic's connectivity. I've had two hubs now, and they both behave the same.
Have you tried just rebooting the Flic hub, rather than resyncing the Hue, to see if that fixes it? If it does, then it sounds like the same behaviour as mine – and I'd suggest there is a problem with the Flic Hub.
Cheers,
Mark