I have seen hot disks being caused by firmware bugs etc but this is consistent depending on which port.
Have you considered somehow different adapter speeds have been introduced... certainly wouldnt be best practices but maybe someone has used a 2gb SFP or something on the a loop and 4gb on the alternate..
Are you actually seeing any problems? Disks on path X being used more than disks on path Y might be perfectily normal, it could be by design. Have you checked which is the primary path on the controllers? My guess is that A is primary path. If A is primary path then fine. The other thing you need to look out for are LUNs with multipathing issues. I dont even know if you ve got LUNs here but
from experience I know that AIX LUNs and Vmware needs to have pathing setup properly.
Yes it could be "normal", but in this case we are having performance issues on this system and I'm trying to find out which components actively participate in this issue. Anything out of the ordinary is suspect until cleared