All router lights flash at same time!!

[#1]

Ok i have previously had a fault ticket and BT have been out and carried out some repairs, the paticular fault has now gone......however i now have a new problem!!!

Before i raise another ticket i thought id ask on here.
What happens is:
On my router - the technicolor TG582n  the green power light remains on steady but all other lights flash green at the same time(all in tandem) for around 15 seconds then all returns to normal. During the time flashing i lose connection to any games im on on xbox live and web pages freeze. Then once they stop i get everything back. (kicked off game servers though).  When i check in the router it has not seen it as a disconnect and the connection still states as being up for however many days.

Is it a faulty router? or is there some way i can solve this in settings?
Any help is much appreciated.

[#2]

I'd be tempted to do a factory reset, and and it continues, try a new router.
If it's from us (which I presume it is) and it's less than a year old, we'll send out a free replacement.