Yes, this is true. All of the old lever-style safeties used on the SPAS-12, LAW-12, and SAS-12 shotguns are defective, every single one of them. They all left the factory working perfectly and if they haven't already started doing it, they will eventually. What happens is the the internal parts wear in a way that eventually the shank of the safety lever starts to trip the sear and fire the gun, even with no pressure on the trigger. Putting the safety on or taking it off will eventually fire the gun when you don't want to. You can learn more about it here:
www.spas12.com
Franchi didn't know about this at first and as soon as they found out they did a factory recall of all the guns, where they replaced the orginal trigger group with a new one that has a crossbolt safety, lika a Remington M870. This wasn't until the late 80s/early 90s and by the time the word got out about the recall, the SPAS-12 was banned from importation to the US and the company that handled the imports went out of business. Weather or not that effects you, Franchi stopped making the SPAS-12 in 1995 and was bought out by Beretta not too long ago, so it's pretty much impossible to get the new-style safety anymore, regardless of where you live. Sorry.