It depends what you consider a major issue. I know that two penny stocks that I have invested in have both had problems that have at least in part been attributed to NSS.
I've referred to the LFWK situation already. The other stock is AURC which has been on the Reg SHO list for 59 days now.
There is no evidence of dilution or toxic funding for either stock and yet the PPS for both were driven down to very low levels which was a major issue for me I can tell you.
Time will tell whether or not there is substance in the NSS allegations.
News 
Market Data 
Discover 
