I have a pair of RV042 with a gateway to gateway VPN running.
Every few hours we loose access to the LAN on the other side of the VPN. The VPN shows as connected at both sides, however no traffic will flow, pings time out etc. Hitting disconnect will make the pair reestablish the connection and it will work again for another few hours.
On the latest firmware at both ends, here is a snapshot of my VPN setup with IP and key blanked.