So got to the bottom of what is causing this (sort of):
The date and time and timezone 100% correct on Synology AND the Windows 10 client used to copy files to the NAS Server.
Upon copying - completely wrong dates for DECEMEBER 2018 are entered under the META DATA 'Added' attribute.
If I put the titles that were "stuck" back in time, and change the ACTUAL new titles to todays date then it all works like expected it should.
Is this a date conversion bug? The newest titles said 11/06/18 and the date picker when entered then said a different date - but it could be one is shown as American and then the correct regionalisation when the picker UI is entered?
I'll monitor for now - but I genuinely hadn't done a thing - and I have copied NEW movies over almost daily - yet the dates were all odd that the system THOUGHT they were added. So in effect the December 2018 dated ones were still in the future as such and that's why they got "stuck"
Edited by unisoft, 08 November 2018 - 04:06 PM.