It's also worth noting that on the Mapped Application Service table (cmdb_ci_service_discovered) there is a separate UI action 'insert and stay' that for some reason tries to copy the number field across from the record you are cloning, rather than ignoring it, so you can't use insert and stay for mapped application services after the Paris release without amending the UI action:

find the part of the script that looks like this:

if (fName.startsWith('sys'))
continue;
if (fName.startsWith('view'))
continue;
if (fName == 'layer')
continue;

and add an extra clause:

if (fName == 'number')
continue;

then you can use 'insert and stay' on mapped application services just ike any other record, and the autonumber will allocate the next sequential number.