Hi, you need to change the field id to 50000~99999 range.
This is a bit different from the idea in NAV. In NAV, we always add the same ID as the standard, which can automatically transfer data when TransferFields is run.
But now in SaaS, if you need to add fields to standard tables, you cannot use IDs from 1 to 49999 range, because Microsoft may use them at any time in future versions.
PS: There is no limit for your new table, you can use 1~49999.

Hope this info will help.
Thanks.
ZHU