Minecart falls through V-shaped rails

Steps to Reproduce:
1. Make a V shaped rail (as on a screenshot)
2. Put a minecart
3. After some time it falls through
After it has fallen it behaves weird. For example, if it gets pushed by another minecart, it'll move, but it will stay under the rails (you can see another minecart on the left in the sand)
EDIT: it happens only when spawning Minecart entity (via /summon command) and not MinecartRideable