Hi,
This should not happen unless you've modified the code of the show_block_dimensions view file, or you've changed the type of the dimension columns from decimal to integer in the hikashop_product table in your database.
Supposing you didn't change the show_block_dimensions view file, the code there expects a number with three decimals, as stored in the database, like 10,000. And so it trims the zero decimals so that it would look like 10 on the frontend.
But if you provide it with an integer like 10, then it will trim the zeros on the right because the code doesn't expect an integer.
Can you provide a screenshot of the structure of the hikashop_product table in your database ?
Supposing you've changed the type of the column in the database, you'll have to create a view override of show_block_dimensions to change :
rtrim(rtrim($this->element->product_weight,'0'),',.')
to:
$this->element->product_weight
and same for height, width, length so that it doesn't trim the zeros.