Flightmech
"All air carriers opr (taking-off/landing) within the territory of Japan are requested to avoid using aircraft equipped with PW4000-94 series engines until further notice applicable engine types are as follows
PW4052 PW4056 PW4060 PW4062 PW4062A PW4152 PW4156A PW4156 PW4158 PW4460 PW4462 RMK : EXC MIL ACFT"
That doesn't seem to have made it into any of the mainstream or aviation media. What's your source, and what does it say is the reason ?