Hello @aga2442
I have never heard of Chromes Hidden tab’ feature – so just do some research on Google. Seems it is brand new and only supported from chrome Version 77 tp current.
It is a touted replacement for Google Synch (apparently it is faster). Also seems that the feature is still buggy – you should check this checklist – it suggests 5 things to check and do to fix bugs
https://www.guidingtech.com/fixes-chrome-send-your-devices-missing-not-working-issue/
Chrome sync works fine with a3 Lazy Load so it should with this new feature – but Chrome may continue with it or maybe not – before we go spending time digging into it and debugging it – I’d like to see it become a lot more ‘mainstream’
Please let me know what you find once you have been through the post 5 things to check.
Steve