Output class names return ungiven classes

[CYBruce]

Following the clearly-written README, I implemented the model successfully.
However, for my cases, I found some problems.
I used the code grounded_sam2_local_demo.py and the prompt is "car . bike . people . parking sign . parking entrance sign ."
But the return json file give some ungiven classes such as "sign entrance sign", "entrance sign"(seems like combinations of prompt words). And sometimes, void class name "" is output.

I want to ask if only classes in the prompt will be labeled by the model. If the question is true, where are the results like "sign entrance sign" coming from? Is this problem related to BOX_THRESHOLD and TEXT_THRESHOLD parameters in the code?