We had a problem last night with zoning. Couldn't think of any reason that might have caused the issue. Really appreciated if someone could help me with some thoughts on it. Here is the problem:

A windows server (a)
Powerpath 5.3
Had disks from 'x' & 'y' symmtrix.
we Need to add disks from one more symmetrix 'z.

On San-01 we have following active zones
(a,x) &
(a,y)

Added One of the FA from symm 'z' in to the zone (a,y) to make it (a,y,z) --> for a migration purpose.
After activating the zoneset - we had no issues with paths to disk on 'y' symm but the paths to disks on symm 'x' degraded.

Could someone please help me with some thoughts on why did the paths to symm 'x' degraded.

We backed out of the change and everything was normal again.