Does unflatten enter into infinite recursion on function or array members?

I'm using this library in an F# project (transpiles to JS through using Fable). So unfortunately I have no JS repro (I'm not a JS dev).

`unflatten` is mostly working fine, but it seems to enter into infinite recursion on some objects. This happens even when there is seemingly nothing to unflatten.

I have an array of key-value pairs (React props) that I'm converting into an object, and then I'm using `unflatten` on this object.

This works fine for some prop arrays, such as this:


However, for others, such as this, it enters into an infinite recursion:



As you can see, in both cases, the original prop list (and thus the object) does not contain keys with the delimiter, and there are no sub-objects to recurse into (unless it does something with the function), so AFAIK `unflatten` shouldn't modify anything.

I have tried `safe` without any effect.

The weird thing is, the stack trace seems to come from the `flatten` function, which I do not call: