There is no latency from CE to PE ,but observing latency when pinging from vlan as source to ASR/DC routers or DNS in enterprise environment?

Reasons for latency

Transmission mediums such as WAN or fiber optic cables all have limitations.Propagation is the amount of time it takes for a packet to travel from one source to another .Routers take time to analyze the header information of a packet as well as, in some cases, add additional information. Each hop a packet takes from router to router increases the latency time.Storage Delays can occur when a packet is stored or accessed resulting in a delay caused by intermediate devices like switches and bridges

Please check all users are facing this issue or a particular user and also check for which application you are facing this issue so you can isolate the problem as much as you can.