Looking into it.
I was able to replicate the problem. IMO the check should be...

Contribution Date
Technology
Drupal
Contribution Project
Commerce Point of Sale (POS)
Contribution Details

Looking into it.

I was able to replicate the problem. IMO the check should be made based on whether the product has fraction quantity allowed or not. I will check how Commerce core does it OR what it has.

Contribution Author
subhojitpaul
Contribution Issue Link
Decimal quantity breaks checkout: "Quantity is not a valid number."
Contribution Link
https://www.drupal.org/project/commerce_pos/issues/2951783#comment-12544212
Files count
0
Patches count
0