Square. They implemented BIP-177. Coming soon to everywhere, because it makes a lot of sense.

BIP 177: Redefine Bitcoin's Base Unit

Read BIPs like a pro.

It's confusing for no good reason. Same situation as with the Russian ruble being scaled down by 100, except that issue was confined solely to the Russian populace, and communicated clearly to Russian residents by the Russian government before adoption. The words "satoshi" and "sat" are already well-established, so just adopt a standard symbol and abbreviation that, and encourage exchange platforms etc. to adopt it as the standard. "BCS" or "SAT" works for an abbreviation/ticker, and we already see "≡" with a vertical line as a prevalent symbol, though alternatives such as "$@" are also somewhat common already.