Don't specifically see it but it may be trying different routes because of peering problems between verizon and whatever ISP serves OOMA. Their are lots of reports of some peering disputes between the various companies.
And yet I know one OOMA user in NY who says he hasn't seen any problems. Still it could be regional. I think i've seen verizon servers with 157.x.x.x listed in other peering disputes. Not sure which area of the country they are in. California?