select() & gsk_secure_soc_read() questions

I've done some socket programming in my past, and select() has been my
go-to to prevent hanging reads. Something isn't working in this case.
We've purposely asked the vendor we're sending to to not send a response in
order to test our timeout code. That appears to be working, at least on
their end. My tried-and-true method of ensuring that I don't hang on a
read when there is nothing there, is not. Below is what I have going on.
In essence, select() is returning right away with 1 as though there is
something available, but soc_read() hangs forever until something happens
(several minutes) and the read is terminated.

So, has anyone seen something like this before? Is there another method I
can use?

int amtRead = 0, totalRead = 0, select_rc;
fd_set read_set, write_set, error_set;
struct timeval timeout = { 10, 0 }; // 10 second timeout
FD_ZERO(&read_set);
FD_ZERO(&error_set);
FD_SET(sd, &read_set);
FD_SET(sd, &error_set);
timeout.tv_sec = TV_SEC; // reset this on every new iteration.
timeout.tv_usec = 0;

do {
if (bDebug) {
CERR2 << "calling select()...\n";
}
select_rc = select(sd + 1, &read_set, NULL, &error_set, &timeout);
if (bDebug) {
CERR << "select_rc=" << select_rc << '\n';
}

if (select_rc == 0) { // TIMEOUT
break;
}
else if (select_rc == 1 && FD_ISSET(sd, &read_set)) {
timeout.tv_sec = 0;
timeout.tv_usec = 500000;

//Read via TLS
rc = gsk_secure_soc_read(my_session_handle, buff2,
sizeof(buff2), &amtRead);
if (rc != GSK_OK) {
sstr << "gsk_secure_soc_write() failed with rc = " << rc <<
" (" << gsk_strerror(rc) << "), errno=" << strerror(errno);
throw runtime_error(sstr.str());
}
// keep an accumualtor going
totalRead += amtRead;

...
code continues...