Checkpoint VPN1-Edge connectivity problem

In my company we use for our remote sites the Checkpoint VPN1-Edge
firewalls. We make very few configuration on it: we don't create any rules ,
we don't use the dmz port, we use those devices almost only for VPN
encryption to connect the remote lans to our central firewall an ADSL or
HDSL Internet connection. On some of those firewalls we recognised a strange
problem: sometimes, without any visible reason some nodes lose all
connectivity between the node itself and Internet. The router is always
working, and the lan connectivity for the node too. The only solution we've
found is to unplug the firewall power cable: after that the situation
becomes normal again.. We have about 5 of this devices and 3 have already
shown this problem. Our reseller doesn't know any particular problem on this
model of checkpoint firewall so we don't know what to do ( we have to buy
many other vpn firewalls). Anyone has already experimented this problem?
There is a solution or it's an hardware/software factory fault?

 

Thanks 

 

BlindHorizon