Regarding the event that a variation cannot be selected

[kkhys2]

We had an event that prevented the selection of variations on the product page.
We are using Hydrogen v1.

The variation selection part is using the default template as it is, and there is no original implementation.
This event seemed to occur only to a specific person and was resolved spontaneously without any confirmation on the part of the engineers.

Sorry for the vagueness, but if anyone has experienced a similar case, I would like to know the cause and solution.
Thank you in advance.