There is absolutely nothing weird about a reputable casino failing to complete a user's kyc verification request, the reason for the failure will usually be attached to what ever email or message they sent to the user.
It's one thing to provide a KYC documents for casino to verify, but is another thing for those documents to be able to get verified, because you may think that you have provided a good document to the KYC team but after examination of the document their can fine out that the document did not comply with the requirements and that could result into you KYC not going through at most times, I have not experienced such troubles getting my account verified before because before I initiate the process, I make sure to have read and understood all that is required and providing them accordingly, the recent cryptocurrency casino I did KYC verifications on in recent time is stake and the verification process was asap, because of the document I provided for that verification.
For the several reputable online casinos I personally have used, they usually don't surprise their users except those that want to be surprised, that is, if you read their documents on withdrawals, they usually explain how accounts with certain level of verifications are limited to certain amount of withdrawals every 24 hours, week or month, and if you are in a low level kyc rank and are going to withdraw funds that is above the limit for that rank, you will be forced to submit documents that is required for the next level of their account verification levels, failure to submit the requested document is what usually lead to the casino's failure to verify the user and process his or her withdrawal.
Majority of those that run into KYC issues are those that failed to read the terms of service of casinos and just assuming that everything goes, the reason you don't expirence such is because you don't failed into the category of lazy cryptocurrency casino users who can't read the terms of service of a casino before making attempts to play on them and when they run into issues they come back to give such feedback as this threads.