Gaps between sprites

I’m trying to create a platformer but have an issue with a gaps appearing between elements used to create the platforms.

If you look at the screen shot, you can see a black vertical line between two parts of the bottom platform. The left-hand side is a tiled sprite and the right-hand side is a sprite. Everything is perfectly aligned on a 35x35 grid with elements 70x70.

It all looks good on the desktop but if I preview the game on a mobile the artefact sometimes appears. It seems to be associated with the camera position as it only appears at certain points when I move the character.

I presume it’s an issue with pixel alignment and different scaling on the mobile, but is there anything I can do about it?

I’ve tried the pixel perfect option in the game settings, but it made no difference.

I’ve also tried forcing the camera position to integer pixel differences, but that made no difference either.

I know I could work round it by using a panel sprite, instead of butting the sprite up against the tiled sprite, but I’d like to know if this is a common problem and there is some setting or trick I’m missing.