@bufanda @wtdrisco What I mean by suppression of "instruction sets" is different generations of CPUs, have different extensions to the standard 64bit ones.
As the generations change you can get sometimes some of the extensions, being dropped physically from the CPU, but also new ones being added.
Since pools are supposed to all be the same, in order to cope with this the hypervisor software stack suppresses (removes or hides), the extensions to instruction sets which aren't common across other pool members.
So for instance if the majority of the pool has this https://www.intel.com/content/www/us/en/products/sku/237569/intel-xeon-gold-6544y-processor-45m-cache-3-60-ghz/specifications.html, while others of the same pool has https://www.intel.com/content/www/us/en/products/sku/139940/intel-xeon-gold-6138p-processor-27-5m-cache-2-00-ghz/specifications.html.
If you look at the instruction set extensions see which ones are, on both (these will be preserved and usable). Then which ones are not, these will be suppressed.