The issue can be hit using the following scenario:

1. Dynamic logical interface (IFL) is created on the physical interface (IFD) for ESSMD subscriber.
2. Traffic is sent via this the IFL.
3. IFD is disabled.
4. MTU is changed on the IFD.

After the step 4, the IFD counters for packets and bytes in both incoming and outgoing directions are decreasing one time. The counters can be seen in the output of 'show interface <IFD name> detail'

After IFD is enabled again, the counters continue growing as expected.

The root cause has not been found as the issue is not reproducible.