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I'm guessing that this is because of the fact that an eccentricity of exactly 1 is practically impossible to exist, but I'm not sure...
Would you like to share your P2002 P2 (SOHO) addon? Are you using SE 0980e?
Comet "P2002 P2 (SOHO)"
One thing that I would like to point out (even though it's kinda irrelevant to the problem) is the "Radius" parameter.
It's a bit of a long explanation, but basically, having an object (especially asteroids and comets) in Space Engine without a known size can be problematic. I once added a comet without mentioning "Radius" nor "AbsMagn" (which can also be used as an alternative to find the size, given a geometric albedo that is already assumed by Space Engine) because JPL didn't have any physical parameters about it, and guess what: It turned into a gas giant, despite the fact that I already labeled it as a comet. Sure, I can just say "Radius 0," but the information on the left will look a bit messy. So, I decided to put 0.0007 (0.7 meters) for irrelevant reasons.
Regarding the SE verson that I have... not really. I'm currently still using the regular SE 0.9.8.0, without the "E"...