The "$sql" variable in that errorneous cases is:

string 'date_migrate' (length=12)
date_migrate;

array
0 => string 'mantis_sponsorship_table' (length=24)
1 => string 'id' (length=2)
2 =>
array
0 => string 'date_submitted' (length=14)
1 => string 'last_updated' (length=12)
3 =>
array
0 => string 'date_submitted_int' (length=18)
1 => string 'last_updated_int' (length=16)

$sqlarray format: http://phplens.com/lens/adodb/docs-datadict.htm