The xtkBuilder.GenCreateOrUpdateSchemaSequenceDDL function is really cool to change the sequence of an existing schema.
It is used by the postUpgrade process, for example to go avoid the use of xtkNewId in old builtin schema.
But this function doesn't manage negative values : when it creates the new sequence, it use the 0 as min value. As some sequences can go to negative values (XtkNewId does), the sequence creation failed when it try to get the current value of the old sequence.
We had errors on a postupgrade last week in stage (the postupgrade worked, but several days after, we noticed that we cannot create new nms:group list beceause the sequence were missing). We fixed that by editing the SQL Code generated by GenCreateOrUpdateSchemaSequenceDDL, taking in account the old sequence min value.