The ATF changes Springfield mentions, is the ATF proposal on pistol braces and guidelines on what’s a pistol and what’s potential going to be considered Short Barreled Rifles (SBRs), thus requiring ATF paperwork as described by the National Firearms Act (NFA) law passed by Congress. It contains a point system that includes whether the firearm has a pistol brace, overall length of pistol, weight of pistol, and God knows what else. Points adding up over a certain amount, and it will be classified as a SBR. The way the proposal was originally written, almost all current AR and Pistol Caliber Carbines (PCCs) with or without braces would probably fall under the SBR classification thus requiring following NFA rules, ATF paperwork, and perhaps a $200 tax stamp current required when buying/creating a SBR.
To answer your question, most likely yes, the Saint Edge AR15 pistol would likely fall into this new rule classification if implemented, if it came with a brace, or has a short barrel (7”, 10”, etc.), or exceeded the point system defined by this ATF proposal (which hasn’t been formally approved or implemented, as the ATF is still reviewing comments on said proposal).
Also, keep in mind, this proposal doesn’t only affect Springfield, it affects all firearms manufacturers that produce these type firearms and that meet the qualifications of what the ATF would now considered to be a SBR, (which was specifically written to target these type firearms, at least that’s my opinion).
I hope this helps and explains your question if I understood it correctly.