Most banks hold payments. I’ve got a 47 year credit history, 800+ FICO score and accounts with about a dozen+ different banks. Only 3 banks instantly credit my accounts. It’s some bank’s algorithm, including Goldman Sachs, and it’s the standard business practice of other banks.
In your case you made unusually large payment and the algorithm flagged it. You’re assuming that just because the funds don’t show in your account GS has received them. That’s a false assumption. The funds typically take 5 to 7 calendar days to reach the bank. If your account becomes overdrawn at anytime in the next 30 days, your bank can demand the return of funds from GS. These are federal regulations.
Hopefully you can start to see the risk banks take in instantly crediting a payment to your account. When did you open your Apple Card account?