Random RTI ID's generated for new employees

Can a random number generator/something similar, be used when creating the RTI ID's for new starters. We have recently encountered an issue taking over a payroll, where a couple years ago they had a couple 100 employees who have since left. We were not made aware of this and new employees on Paycircle have now had an RTI ID generated that already existed for that payroll, albeit on a different employee a couple years ago who has now left. The employee who left is now unable to claim their Universal Credit as HMRC have captured an RTI submission in their name, despite them leaving the payroll.

It is already hard enough to get the correct information when handing over payrolls, let alone expecting previous agents to provide us with historic RTI IDs from previous tax years in the event that it might be relevant.