Why did my 4x5 asset appear in landscape placements?

Assets are mapped to their relevant placement by their position. Per default the Placement Customization settings expect a 16x9 asset in the third position.

When you upload three assets, e.g. 1x1, 9x16 and 4x5, the third asset will appear on all placements that are currently selected in the Placement Customization Settings, per default those are Facebook Right Column, Facebook Instant Article and Facebook Search Results.

How to fix:

Update the placement settings or reorder your assets.

Step 1: Navigate to the Settings

Step 2: Choose the "Single Image or Video Ad" Setting and remove the three placements currently used for the third asset.

Step 3: Add the placement, where you want your 4x5 asset to appear, e.g. Instagram Feed.

Step 4: That's it. You can now continue to upload your assets using the 4x5 asset in the first position.