Pilots in Boeing aircrafts are not allowed LNAV/VNAV when using QFE below transition level/altitude...there are possibilities of turns and manoeuvres based on altitudes achieved as conditional waypoints which are " hardwired " and cannot be changed through FMC LSK manipulation.
One can argue that where altitude based conditional waypoints are absent, there is nothing preventing pilots from altering the altitude constraints to enable LNAV/VNAV operation below transition level/altitude but I guess Boeing and the FMC manufacturers are just covering their arses just in case.
The bad and pesky thing about altitude based conditional waypoints is that one also cannot alter them to factor in cold temperature altitude correction. Hopefully I guess the chart designers had already factored that in conservatively when they promulgated their procedures. Strangely, they had never had the caveat that certain SID/STAR not be flown using LNAV/VNAV below certain temperature unlike certain RNAV/GPS minimums that cannot be used as such.