First off, the firewall blocked it correctly so it doesn't really matter which IPS signature got matched.
But to answer your question if I am reading the CVEs correctly, MS10-012 (Microsoft SMB server race condition denial of service- CVE-2010-0021) was the ability to corrupt and crash the system (DoS) through a vulnerability in the SMB v1 server and was revealed in 2010. MS17-010 (SMB Remote Code Execution - CVE-2017-0143) appears to be very similar in that it is the weaponization of that earlier vulnerability in 2017 that can execute arbitrary code via SMB v1, instead of just cause a DoS. So to me it looks like the same vulnerability with just different outcomes (DoS in 2010 vs. running arbitrary code in 2017). In that case it would make sense that the 2010 IPS signature would get triggered, even though your kit was attempting the 2017 code exploit as they are basically the same thing, just different outcomes. I don't think your exploit got far enough to inject the arbitrary code before the 2010 IPS signature was triggered and stopped it.
Check out this other CheckMates thread which is very similar to your situation:
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