The article stating that is a headscratcher for sure, but for over 100 years, levers have been using RN bullets, without incident. What would you go with, time tested or what a article says is "new information"?
In the last 20 years there has been a rumor that round nose bullets can cause a detonation in the tubular magazines. No proof has been provided to my knowledge. Remington, Winchester and Federal still sell loaded ammo with round nose bullets for their 150 gn and 170 gn cartridges.
I just shot another 50 using Lyman 311291 bullets yesterday and am still here in one piece.
I shot some more FTX rounds today as the wind had died down. I started out zeroing at 50 yards then moved to 100. I thought I had it dead center on the bulls-eye but the last 2 rounds were off. The barrel was pretty dirty by then so I'll try again maybe tomorrow (the wind is supposed to kick up again though) at 100 yards.