No never bent a NP MXT RDM nor did it seperate from the base. Have both the first model MXT (2008) and the newer model(2012 onwards). The old model I use occasionaly use as a backup when I want to rig 2 sails. The newer model is still going strong after 5 seasons and 100+ sessions of abuse and high tension in my NP Evo's.

By far the best extension I've ever had. Yes it costs a lot of money but you won't ever want to go back to another brand.

Have had several other brand (Prolimit, Unifiber, Chinook, etc) alu and carbon extensions and nearly all bent or broke after time.

Not addressing NP, in particular. Aluminum will bend , carbon will break. I see neither as being trouble. What's most common is the longest one being used to full length.
I think the cost difference plays into the choice most.

Weight is a factor, but you could save more weight using K4 fins than carbon to alloy on an extension .

Just saw 2 North rdm extensions fail over 2 days. The plastic cracked.