I know pretty sure EOS HD 802 is RJ-10 DSP. I have few of them, NTSC and PAL versions.
I have no clue what EOS HD 803 is. Probably it is RJ-10+ but prior to "RJ-11 (in which the Korean RJ Electronics is sold/absorbed to China RJ Electronics)".
I don't know if EOS HD 820 is a typo or not.
1) all RJ-10 based video cams do not have "color disappearing" fall-back to B&W mode (under low light) problem.
this include few $25 LN300-10xxx cameras (PQ0133, PQ0134, etc. mostly OOS), AVS $25 DIY cam (if it is still in stock), and perhaps the new "unknown 803/820 cams".
2) other than special firmware mod, RJ-11 NTSC version (11672, 11810) will have that color fall-back to B&W mode "issue"
<-- for astro low light use, it may be viewed as disadvantages. for security surveilance use, it is beneficial
3) RJ-11 DSP PAL version (11673, 11811) does not have problem stated in (2)
On point #3, mine is color at Brightness 2, AGC set to anything. Soon as AGC is set to High, and Brightness is increased gradually, I very quickly loose my colors, and then long after that bright scenes blow out to almost white. And mine is PAL. I seem to have the only RJ11 PAL LN300 camera on Earth that does this?
Just my luck.