US Date format not working - TYPO3 v8

We are migrating a old TYPO3 system (v 6.x) to TYPO3 v8.7.19. The end client is US based, so they need the dates in the US format. Now, even after setting the [SYS][USdateFormat] to true and [SYS][ddmmyy] to ‘m-d-Y’, things are not working on the server as expected.

We have checked the issue on multiple server, and the issue persists. On 1 server, when we view the date field of records directly in ‘List’ module, few records does display the format in ‘mm-dd-yyyy’, but other records in the same momentarily displays the date and immediately disappears.
Now, when we see these records as inline records, then all the dates are back in ‘dd-mm-yyyy’ format or no display at all.

Please advice, how to fix this. We never expected we will face this issue in TYPO3 v8! After so much years of experience, TYPO3 unable to provide this basic settings for US requirements. Actually, we need the format ‘m/d/Y’, but which looks like not possible in TYPO3. We can convice atleast if we can get the dates working smoothly in format ‘mm-dd-yyyy’.

Please advice us a solution for this.

Thanks & Regards,