I am witnessing the same phenomenon. Only for me, it's more intermittent. I upgraded from Gutsy, but for the record, I have not seen this problem with Gutsy. I have an Nvidia 6800gt card, using the latest nvidia accelerated drivers. If I lock the machine, the screensaver activates as usual. I will test further, and report findings as I notice them.
I am witnessing the same phenomenon. Only for me, it's more intermittent. I upgraded from Gutsy, but for the record, I have not seen this problem with Gutsy. I have an Nvidia 6800gt card, using the latest nvidia accelerated drivers. If I lock the machine, the screensaver activates as usual. I will test further, and report findings as I notice them.