What really surprised me is the check didn't say "debtor in possession." I think there are more guarantees when a check is a DIP check issued thru bankruptcy court supervision. Regnis might know.
I don't understand your concern with the time frame hold. Are you really worried about the check bouncing? If you had a legit concern then why didn't you just take the cash? I'm a bit confused as to why you keep pressing the issue about the hold?