Could be incomplete pollination. Do they taste OK? Do upload pics if you can.

it tastes ok but not great

Are they all like that or just one?

Also, are these your first fruit off the plant, or did they start doing this after producing "normal" fruit for a while?

I THINK its all from the first crop. They started like this.

Abnormal locule development is a result of some form of genetic manipulation that affects the ovary early on in development. That gene mutation can be either intentional or accidental like the use of auxin or gibberellin supplements, intentional manual cross-pollination with another variety, internal ethelyene gas development due to environmental factors (since it appears to be way over-ripe that is a real possibility), etc. But this one looks almost parthenocarpic which would indicate the presence of some sort of A or G supplements.

But without the name of the variety we don't know if it was supposed to be bilocular that is just malformed or multilocular that only developed 2 instead (that would be my guess).

That knowledge would narrow down the possible causes toward helping prevent it in future plants but either way it won't help this (these) fruit.

Dave

I believe some varieties have a tendency to produce parthenocarpic fruits early on. As Dave says, without the variety name, it's impossible to figure out what exactly is happening.

I canned roasted tomatoes today, which involved cutting 10 pound of tomatoes in half. Almost none of them were completely symmetrical as far as seed placement goes. I think the tomato above is normal.