Loop Detected

So we have PCs that connect to cisco ip phones that then connect to the switch. I noticed this initially on our netgear switch and it just spams loop detected on port 52 which uplinks back to our main server room. So on the other side of the link is just a netgear distribution switch on port 7. It has other uplinks and simply just forwards traffic along. On that switch its showing similar to what's in the picture below. It shows a loop being detected on port 1/0/16 which is a cisco switch. Now the netgear switches are using RSTP while cisco is using PVST. I've been of the mind to have all switches that are able using RPVST if they're able, if not, then RSTP or even MSTP though from my reading MSTP is ideal if you have hundreds or more of vlans. 

Anyways, I SSH onto the cisco switch and do show logging and I see some mac flapping messages that are going between a switch and our meraki firewall. I've tracked that mac address down to a cell phone so not sure if that's what causing it. There's not really any messages explicitly about any loops. . As well the error message states "Loop detected on 1/0/52. But feature is not enabled. Ignoring PDU" I'm not sure what feature it's referring to. I thought I did and I enabled L2 loop protection but it is not like it sounds. So, on that uplink port between 52 and port 7 on the distribution switch i enabled loop guard from CST port configuratoin. I also did the same with the ports between the distribution switch and the cisco switch. But yeah its still just shows a bunch of these messages. So curious if anyone has ran into these errors. I haven't really noticed any issues on our network as far as things being slow or down right inoperable.  If you need me to post a screenshot of anything, let me know.  Thanks for taking the time to read.