It would be better if you could move to latest Intel compiler as even if there is an issue with 11.1 compiler, it will not get fixed in 11.1 ( too old to fix). If the issue is reproducible using 12.x then it compiler team will fix it.
According to my understanding, /arch:SSE isn't a supported option, and any documentation mention of this option is a documentation bug. I do agree, the docs ought to have been fixed earlier. If that option exists, it would seem to be an analog of the former option /QxK which wasn't supported adequately after ICL 8.1. There no longer is a separate SSE math library for ICL; if you want to run without SSE2, you require the IA32 math library.
The only supported option for compatibility with P-III is /arch:IA32. Several ISVs have had to drop support for P-III compatible CPUs, as none of the compiler vendors have the resources to support them properly, and it requires excessive QA on the part of the ISV as well.