I apologize for any inconvenience caused.
I have tested it both locally and on our test platform and it works fine.
Let's see what is happening to you, for that I need you to tell me what decimal separator you have configured in the WooCommerce settings.
If you have configured the commas, it should work (if not, we will continue to investigate).
If you have configured the points as decimal separator, when you enter a comma in the price field, what you say happens if you save, but you get the following warning:
Regarding your second question, it is unrelated, we have recently made a change in that field. When the product does not have the multi-inventory option "Price per inventory" activated, the price field is applied to all inventories since it is the same. When you activate the price per inventory option, you will be able to edit the field, inventory by inventory.
Without the option "price per inventory".
With the option "price per inventory".
I hope I have been helpful