Hamlib source code can be found from GitHub. There the file src/rig.c holds the error code definitions:
List starts from RPRT -0. So we can count errors -13 and -11 to be:

RPRT -11 "Feature not available", that is normal with Icom. They do not support the "v" (show vfo) part of cqrlog's query string "fmv" but cqrlog will work without that ok.

RPRT-13 "Communication bus error", you have some problem(s) with rig connection.
Is the baud rate correct?
If you are using USB it might be that highest speed 115200 does not work properly (at least with my ic7300 it causes random errors).
The highest speed that icom can use with USB and CI-V socket connected together is 19200. That is fast enough and works very reliable.

At Icom's side you have to disable setting "CI-V tranceive" and if you use USB cable instead of CI-V remote cable you have to enable "CI-V USB Echo Back". Without these rigctld will not work properly.

/*
* Careful, the order must be the same as their RIG_E* counterpart!
* TODO: localise the messages..
*/
static const char *rigerror_table[] =
{
"Command completed successfully",
"Invalid parameter",
"Invalid configuration",
"Memory shortage",
"Feature not implemented",
"Communication timed out",
"IO error",
"Internal Hamlib error",
"Protocol error",
"Command rejected by the rig",
"Command performed, but arg truncated, result not guaranteed",
"Feature not available",
"Target VFO unaccessible",
"Communication bus error",
"Communication bus collision",
"NULL RIG handle or invalid pointer parameter",
"Invalid VFO",
"Argument out of domain of func",
NULL,
};