I'm having a similar issue, and I am wondering if it is because the IDE is incorrectly trying to read registers that are write-only. For example, I'm using a J-Link with a KW31Z. Register SIM_SRVCOP is Write-Only, but looking at the GDB logs, it is being read!
030,167 (gdb)
030,168 312-data-read-memory-bytes --thread 1 1074036996 4
030,180 312^error,msg="Unable to read memory."
030,180 (gdb)
I suspect this error is propagating back and causing the memory view to not show ANY of the given peripheral registers. So, for me, the SIM registers don't work at all but some of the other do (and they have no read errors).
The XML description file that I can find in the SDK loaded for this processor lists SIM_SRVCOP as write-only, is the IDE ignoring this?
<access>write-only</access>