Hi,
That is strange. I looked up the configuration, I don’t see that field anymore in the post editor. On the ACF options, there is only one field in the bin, and that is “start_date” and not “start-date”.
I queried that weird “start-date” field value via FTP, and it does not contain the date in MySQL datetime format, but as a custom date format, which is not comparable. ACF does not do that, they use a display value, but the field is always stored in the correct datetime format.
I recommed creating an ACF date or datetime field, and using that, that should work all right. The one you created and have in the bin is perfectly fine, but make sure to change the meta value on the filter to “start_date”.