So this morning I was upgrading our Orion environment with the latest versions of IPAM and SAM and latest hotfixes. The primary poller installer (online) seems to have worked as expected, and I see SRM 6.5 HF1 as an installed update:

However after using the additional poller installer (online), I don't see this specific update applied to the additional pollers. I also don't see this HF in my support portal to install manually. The other HFs seem to have been equally applied to primary and additional pollers.