There was a pending article by GratefulLife which is now on hold because of the grey sheet issue I believe.
Quite the recent run-up here... but as you say, very little volume.
Myself just watching at the moment, wondering if IMMVF will pullback further.
IMV.V has much better volume for this equity, though still low, and on the TSX Venture instead of the greys.
On Interactive Brokers I don't get a quote for IMMVF, just for IMV.V Generally I go with Venture if it's the native exchange and the alternative is OTC or Grey for the greater liquidity.