A confusing and incorrect comment all around.
Exchanges do not receive or handle GTC or GTD orders, see for example the NYSE pillar spec.[1]
Broker-dealers handle stock splits and the behavior varies according to your broker. Some brokers will request the broker-dealer cancel all orders back, but most brokers allow limit prices to be adjusted for orders "below the market" (buy limit orders and sell stop orders). The Fidelity FAQ is an illustrative one.[2]
I'm not sure what a "vendor" is here, but brokers send GTC orders to broker-dealers, who forward them to the exchange every day as a day order. This behavior is industry standard and certainly not bush league.
[1] https://www.nyse.com/publicdocs/NYSE_Pillar_Gateway_FIX_Prot...
[2] https://www.fidelity.com/trading/faqs-order-types