When it comes to the new-style caps used on the 60ml and 30ml Montblanc ink bottles, in the last year I've had two develop cracks vertically across the threads. Could they have been over-tightened? Well, I've never had this issue during decades of twisting the knurled 50ml bottle caps, and I'm confident I use the same amount of torque. My other nine MB bottles with the new-style caps get more scrutiny now.
Have you been working out?
Seriously though, thanks for the heads up..