I don't believe any of us actually has any idea what is causing the vendors to change their websites in the past couple of days, but as for trademark infringement, I always thought Cloupor's decision to include the stickers on the inside that has Hana's name on it was a strange move.
This is what I suspect. Most vendors changed their photos out at the same time to photos from cloupor instead of photoshopped photos of actual Hana units.
Seems like everyone may have gotten a legal threat right around the same time.
Illvapes was selling logo units and referred to theirs as Hana clones rather than Cana modz. So I can definitely see them doing all of this as a knee-jerk reaction to a legal threat.