I don't think that your claim has been supported, since what you were saying is that "It will not work", and what they are saying is it works but there are distorted lines.

I dont think these distorted lines depends on the card it it's been bought from casa or if you copy pasted it directly from the site. The issue is with the iNav itself, I know someone who bought it from casa who also claimed he is experiencing this distorted lines issue.

Someone above said they had to buy a standalone GPS, that's something else, that's not iNav. Now if someone claimed that they bought the gps card from casa and said that they don't experience the distorted lines, that's backing up your claim.

For me I dont use this Navigation that much, it's not cuz of the distorted lines issue but it's because I don't like its route and direction, I only use it as a map for my reference-- you would see establishments and streets around you.

Here's a sample, instead of picture I made a video, no distorted lines: