Shared LUN between VM's

I am new to Hyper-V and have a question about a shared LUN between two VM's. I Have a LUN on a Dell SAN and I have granted access to it to a group of servers within the Dell Storage Manager. I can mount the volume on both VM's  but when I put data on the volume on one server the other server does not see the same data. Is this by design or am I doing something wrong? Can I not mount a shared LUN on two VM's at the same time so they both see the same data?

Thanks in advance!