show decimals wrong

Hello:
I explain my problem with an example.
If in a product you choose the weight with decimals (f.e. 1.5 Kgs) and the price of the kilo is 20 € the pluguin shows 30.000,00 € but in the basket is correct and add teh product with its correct price 30.00 €
?Could you help me? I don′t know why it happens
Thanks in advance

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