Transcontinental Race No. 6 - TCR6 - #TCRN06 - 2018

From reading around

• some are / were duff from the factory. SG7001-11 usually works however.
  
• some get broken when a shift isn't great, caused by too much pedal torque or bad cable tension
  
• poor bearing pre-load makes them mis-shift and leak
  
• changes in pressure can cause them to leak. They don't have a breather hole. Or rather they do but oil leaves with the air.
  
  

That said a lot of people seem to have got good mileage from them. Shrug.