Woocommerce – Apartment, Unit Suite field not completed is restricting checkout

Hi, I have 2 websites with this issue and 4 without – all running Woodmart theme.

One of the ones with the issue, I changed some shipping settings and this fixed the problem.

The other site – I have deactivated all plugins (and I mean even the ones I really can’t live without) and still nothing changes. Not sure why this is an issue on this website and not any any others – one of the ones it doesn’t happen on is running an older version of WP and WOO – so if required I will have to rollback the theme, WP & WOO just to get this fixed. Please help, there must be some other reason this is happening? The 2 plugins installed since it last worked are deactivated and still nothing…