I haven't had any major issues with my KBT Pure or GON board with PCB mounted Cherry stabilisers and all my current SA sets (Penumbra, Nuclear Data, PuLSE, Hack'd by Geeks), although the Hack'd by Geeks spacebar does feel a little "tight", like it has some slight resistance on my wife's GON.
If others have issues with the newest SA sets, could it be that they're not letting them cool enough before removing the molds due to the large number of SA sets they're making nowadays and time pressure? That could cause shrinkage issues and stems not aligning perfectly.
1976 just arrived today at the post office, so I'll report back once I've tried that spacebar.