Leader of indeterminate terminating?

[Maxamillion529]

Hi Folks,

Wondering if anyone can help me understand how this tomato is growing? It is a black russian, indeterminate apparently (https://metchosinfarm.ca/product/black-russian-tomato/) but following its first flower cluster it seems like the main leader has produced a second flower cluster? I was planning to prune to 2 main leaders but not sure what to do now... is there a chance that it is a determinate and I will be cutting production? I have 3 plants, 2 of which have this growth pattern. Also, first year growing lots of tomatoes so maybe this is normal?

Thanks!