Unexpected "nan" in caminfo output

[dpmayerUSGS]

ISIS version(s) affected: >=3.10.2

Description
caminfo produces values of "nan" for the SubSpacecraftGroundAzimuth, ParallaxX, and ParallaxY keywords on certain images, even though caminfo is still able to compute other angles and even project a footprint onto the target body. I have only found this to affect specific MOC EDRs, THEMIS IR EDRs, and THEMIS VIS EDRs.

How to reproduce

moc2isis/thm2isis from=infile to=outfile.cub    #program depends on which image being input, obvs 
spiceinit from=outfile.cub
caminfo from=outfile.cub to=outfile_caminfo.pvl geometry=yes isislabel=yes statistics=yes camstats=yes polygon=yes inctype=vertices numvertices=40

grep "nan" outfile_caminfo.pvl
#    SubSpacecraftGroundAzimuth = nan
#    ParallaxX                  = nan
#    ParallaxY                  = nan

Additional context
Complete list of the affected images:
/pds_san/PDS_Archive/Mars_Global_Surveyor/MOC/mgsc_1029/m03003/m0300359.imq
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10066/data/odtie1_0066/r723xxedr/R72340029EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10071/data/odtie1_0071/r782xxedr/R78241001EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10009/data/odtie1_0009/r094xxedr/R09436025EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10008/data/odtve1_0008/v080xxedr/V08090001EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10011/data/odtve1_0011/v121xxedr/V12120008EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10014/data/odtve1_0014/v148xxedr/V14802004EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10017/data/odtve1_0017/v183xxedr/V18386001EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10017/data/odtve1_0017/v187xxedr/V18763010EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10022/data/odtve1_0022/v236xxedr/V23662019EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10024/data/odtve1_0024/v263xxedr/V26315022EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10024/data/odtve1_0024/v267xxedr/V26737030EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10026/data/odtve1_0026/v280xxedr/V28061017EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10030/data/odtve1_0030/v327xxedr/V32776005EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10033/data/odtve1_0033/v365xxedr/V36572024EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10036/data/odtve1_0036/v399xxedr/V39981004EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10042/data/odtve1_0042/v457xxedr/V45719019EDR.QUB
/pds_san/PDS_Archive/Mars_Odyssey/THEMIS/USA_NASA_PDS_ODTSDP_100XX/ODTSDP_10042/data/odtve1_0042/v463xxedr/V46394001EDR.QUB

[jessemapel]

@dpmayerUSGS We have a little bit of support time slotted right now. We're primarily focusing on various clean-up issues. Is this a high priority issue for PDS-Pipelines or can it wait until the full support sprint in June?

[dpmayerUSGS]

@jessemapel It is impacting PDS project work, so sooner is better than later. I have no idea how simple/difficult it will be to fix this (because I have no idea what's causing it), so I can't speak to whether it makes more sense to tackle during a cleanup sprint or the full support sprint in June.

[jessemapel]

It sounds like we should slot it now and at least get an idea of how much there is here @acpaquette

[acpaquette]

@jessemapel Sounds good. The only issue is that this is going into ISIS 5.0.1 and I know that @dpmayerUSGS is on an older version of ISIS. Should we be planning to back port a potential fix?

[jessemapel]

Let's see how big the fix is before we do that. The ISIS 3 development and testing environment is quite old and may not be fully functionally anymore.