That by itself is not commingling. Money is fungible, and https://en.m.wikipedia.org/wiki/Float_(money_supply) is a well established and widely used concept.

If you send another person’s money to a different person, they effectively came from the same account and are therefore commingled. Your money is fungible, other people’s is not (unless you are a bank).

Some states have laws against floating, some do not.