I've read about that recent issue as well:
Change in VMware 5.5 U2 ATS can cause storage outages! | Virtual Me
My understanding is that if VMware detects VAAI support at the creation of a datastore then only ATS locking is available, with no fallback to SCSI reservations. Am I mistaken about this and should the above configuration be implemented?
Like other VAAI primitives, ATS/offloaded locking can be disabled any time.
You should probably listen to your vendor if they say so, as it really seems to be a confirmed bug. If you're unsure you can contact VMware support as well.