FMC displays NONE instead of selected SID

Hi,I've noticed, when selecting some SIDS from the DEP/ARR page on the FMC, that NONE is displayed at the 1L LSK after selection, instead of the SID name.For example(from memory), at EGCC Rwy24R, selecting SID DEST1R(say), will put that SID in the 1L LSK position, where it appears as such. However, if I select HONN1R(say), the word NONE appears in the 1L LSK position. Of the six or so SIDS available for Rwy24R, perhaps 3 show up correctly, while the others show as NONE. I thought there might be an issue with these particular SIDS, but I experienced similar problems with SIDs at EGLL.In each case, reselecting the DEP/ARR page and the DEP airport will correctly display opposite the selected SID in the SID list. The SID also shows up correctly on the ROUTE page, so this is(I guess) more a minor annoyance than anything else? Still, I would like to know whether this is a known fault and, if so, whether it can be fixed(I checked the relevant pages of the FMC manual, and looked in the SID files, but can't see any likely cause for the problem so far).Thanks in anticipation,FrankPS I know the SID names cited in the example above are not fully correct(I can't access PIC right now), but I believe they still convey the problem.