The stepping back in time would make it a causal loop if you were able to observe something happening in the past (light traveling from the source) from the exi

The stepping back in time would make it a causal loop if you were able to observe something happening in the past (light traveling from the source) from the exit side, then go back through the wormhole to change this. To prevent this, the observed wormhole traversal time would need to be slightly faster than the speed of light, because then you also couldn't go back far enough to change something you already observed (assuming the "time" here is symmetrical to the time it takes going in the other direction). However there are other problems: What happens when I have 2 matching wormhole pairs, each exit being located to the entry point of the other. If I step back through the exits again and again can I go back in time as far as I wish?