Folks:
Had similar issues here, specifically, after directing the plugin manager to the correct path (program files (NOT x86)/universal audio/powered plugins, many of my UA instances on a pre-existing project were still 32 bit/bitbridged.
Not really a huge deal, since BB has worked pretty well for me, but in an effort for Sonar to update ALL older projects with the proper 64 bit UA plugs, I went to the default UA 32 bit install path (for me: program files (x86)/cakewalk/vst plugins), CUT the "powered plugins" folder and pasted it to my desktop, i.e., essentially deleting it from the scan path but keeping it just in case.
I re-scanned plugins, closed the project, closed Sonar (X2, BTW), re-opened Sonar and the same project and ALL the previous 32 bit UA plugs were now 64 bit with the settings intact.
Hope this helps if anyone is having the same issue.