Yes, in our D3XX and D7XX series phones jitter buffer is adaptive.
It is possible to see the jitter buffer values for every call by enabling the RTCP-XR reports.
JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=40 JBX=240
- JBA = AdaptiveJBR = JB adjustment rate
- JBN = JB Nominal
- JBM = JB MAX
- JBX = JB Absolute MAX