Both GDB and LLDB by default will stop when a debugged process receives a signal. Some libraries, such as the mongoose HTTP server, will generate SIGPIPE as a matter of course and that can be “normal”. However, the debuggers stop anyhow.
Google result currently shows this GDB command can be entered to stop the behavior:
handle SIGPIPE nostop
The LLDB equivalent is not obvious, but I found that this will do it:
process handle SIGPIPE -n true -p true -s false