freebsd stable - Aug 2016 - stable/11 -r304029: an isolated "CAM status: CCB request completed with an error" (I've never had such before)

I've never gotten the following sort of isolated "CCB request completed
with an error" before on the rpi2 configuration that I use (many
11.0-CURRENT and 11.0-BETA<?> builds).

So far I've only seen this one "CCB request completed with an
error". I note it in case others also see such on occasion.
> # script ~/ports_typescripts/r419978_typescript portmaster -DKa
> Script started, output file is /root/ports_typescripts/r419978_typescript
> ===>>> Starting check of installed ports for available updates
> ===>>> Launching child to update ca_root_nss-3.25 to
ca_root_nss-3.26
>  
> ===>>> All >> ca_root_nss-3.25 (1/1)
>  
> ===>>> Currently installed version: ca_root_nss-3.25
> ===>>> Port directory: /usr/ports/security/ca_root_nss
>  
> ===>>> Launching 'make checksum' for security/ca_root_nss
in background
> ===>>> Gathering dependency list for security/ca_root_nss from
ports
> ===>>> Initial dependency check complete for security/ca_root_nss
>  
> ===>>> Returning to update check of installed ports
>  
> (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 15 f4 42 40 00 00 80 00 
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): Retrying command
>  
> ===>>> All >> (1)

Context details:

# svnlite info /usr/src | grep "Rev[i:]"
Revision: 304029
Last Changed Rev: 304029

# uname -apKU
FreeBSD rpi2 11.0-PRERELEASE FreeBSD 11.0-PRERELEASE #4 r304029M: Sat Aug 13
01:10:34 PDT 2016     markmi at
FreeBSDx64:/usr/obj/clang/arm.armv6/usr/src/sys/RPI2-NODBG  arm armv6 1100500
1100500

# svnlite info /usr/ports | grep "Rev[i:]"
Revision: 419978
Last Changed Rev: 419978


==Mark Millard
markmi at dsl-only.net