Pin constraints not breaking in 4.x?

[autopsyturvey]

Hi

I'm having difficulty getting pin constraints to auto-break (using Break Resistance) since upgrading to Obi 4.x (4.0.1).

In my game, I'm adding pin constraints and altering their pinBreakResistance via code, which worked in 3.x, and have also tried setting up a test-case in the editor. 
Either way the pins aren't breaking under duress, even with minuscule breakResistence values.

I posted this in general as I am having the same problem with both Obi cloths and Obi ropes.

Can I just check this is not a bug?

Thanks in advance

Ric