Scenario: A check was presented that was either missing an endorsement or was post-dated. The check was held for an extended time and was returned.
That endorsement has been obtained (or the date corrected) and now the check is being prestented again.
Could another extended hold be placed or do we have to stick with just a regular hold.

You can't place another exception hold on the check in the situations you've described. This "exception to the exception" is very clear in the reg.

12 CFR 229.13(c) Redeposited checks. Sections 229.10(c) and 229.12 do not apply to a check that has been returned unpaid and redeposited by the customer or the depositary bank. This exception does not apply —

(1) To a check that has been returned due to a missing indorsement and redeposited after the missing indorsement has been obtained, if the reason for return indication on the check states that it was returned due to a missing indorsement; or

(2) To a check that has been returned because it was post dated, if the reason for return indicated on the check states that it was returned because it was post dated, and if the check is no longer postdated when redeposited.