My friends and I have found that we all get residual visuals from the first use of 2C-I, but not the same as HPPD.
Here's how it worked for me:
1st trip - I only took enough to get spider web effects in the dark. It never went away (1.5 years now?), but is lessening and can only be seen in very dark conditions
2nd trip - Took enough to get persian carpet patterns on popcorn ceilings. That stayed with me only when I zoned out for a little while and stared at ceilings until my 3rd 2C-I trip.
3rd trip - Took a little more and got flowing visuals when I relaxed on most things. This increased my afterwards visuals to the same level on some surfaces when I zoned out for a while.
This lasted for about 1 year exactly. The first 7 months it was exactly the same at all times, then suddenly it started dropping off and by 1 year in I couldn't see them at all anymore.
My friends who took 2C-I experienced almost the exact same thing. None were bothered by it, as it only affected us when we zoned out and it was very pretty. I almost miss it.
Here are some interesting things though, I took 2C-E twice before at much higher levels and experienced no lasting visuals. I took 2C-C at a strong level about 6 months into my recovery period and it didn't affect my 2C-I residuals at all. This makes me think that 2C-I is unique in this regard.
I now have slight HPPD visuals including static, floaters, etc, and they are were nothing like the 2C-I residuals. They are much more annoying, not beautiful, and don't take a while of zoning out to appear (they are constant). They also included mental effects, which the 2C-I visuals didn't. My 2C-I visuals are completely gone.
I believe that while 2C-I may be able to cause HPPD as all other psychs can, it also has a special 2C-I residual visuals effect that is different from from standard HPPD. It fades within a year of non 2C-I use and is not effected by other 2Cs.
Anyway, that's just what my small study of four people (my friends and I) have found.
Hope this helps someone!