Minecarts with TNT not pushing player

The bug

Minecarts with TNT, when activated, don't seem to push/launch a player when activated with an activator rail.

How to reproduce

1. Place two rails (one of them must be a powered activator rail)
2. Place a Minecart with TNT and push it towards the activator rail
3. Stand next to the flickering Minecart with TNT (in survival) and let it explode
   → You will take almost no knockback/won't be launched

Code analysis

Code analysis by Marcono1234 can be found in this comment.