After upgrading 2 switches from 6.47.10 to 6.48.6 I had the same issue. The models are:
CRS312-4C+8XG-RM
CRS326-24S+2Q+RM

These are both MIPS architecture.

These are both running in a multiple vlan environment with a trunk connection to a router. IP addressing is /30 + /126 over a dedicated vlan with a /32 + /128 loopback bridge interface. These are part of an OSPF network.
This works fine on 6.47.10, however, with 6.48.6 there is no v4/v6 IP connectivity. Not to the loopback address or the vlan ptp address.

I have also done this ROS update on a CRS328-24P-4S+RM switch (ARM architecture), however, the setup is different here. It has a multiple vlan setup but IP addressing is simply attached to the main bridge and just participates in one of the port vlans. No OSPF is used.
This ROS update also works normally in this case and on all my other devices (AP's and routers) which are all ARM.

It is not clear whether this issue is due to the difference in config which the update has broken, or there is something wrong specific to MIPS. Has anyone encountered this and can shine a light on what is happening?