My tank is 3 years old and has been thru hell and back. No cracks.
I think it is a quality issue with the mold process. If you overheat the plastic to flow faster into the die to speed production you can get brittle failures. Just check out zip tys - you can get a batch of over cooked ones that snap anytime you flex them gently.
2013 Ducati Hypermotard SP, 2011 Husaberg FE570S, 2011 BMW S1000RR, 2010 BMW F800GS
2007 Husqvarna TE610 , 2003 KTM 525 MXC