Does anyone know what might cause this chunk of code to sometimes run ok and sometimes throw up error messages?

drop table if exists mapping_rules;

create table mapping_rules
(
    claimant_type char(50),
    tpd_flag char(10),
    tpi_flag char(10),
    mapped_claim_type_1_high char(30),
    mapped_claim_type_2_detailed char(30),
    mapped_claim_type_3_high_ex_recovery char(30),
    mapped_claim_type_4_detailed_ex_recovery char(30)
);

bulk insert mapping_rules
from '>>>censored-filename<<<.csv'
with (format = 'CSV', firstrow = 2);

-- convert TRUE and FALSE to 1 and 0

alter table mapping_rules
add tpd_flag_2 int,
    tpi_flag_2 int;

update mapping_rules
set tpd_flag_2 = case when (tpd_flag = 'TRUE') then 1 else 0 end,
    tpi_flag_2 = case when (tpi_flag = 'TRUE') then 1 else 0 end;

The error message I sometimes see is:

Msg 207, Level 16, State 1, Line 25
Invalid column name 'tpd_flag'.

Msg 207, Level 16, State 1, Line 25
Invalid column name 'tpi_flag'.

Strangely, if I run this code one command at a time, it always works. The errors only appear if I run the whole thing at once.

Also in the code editor, tpd_flag_2 and tpi_flag_2 are red underlined, so presumably there's a problem...? I can't figure out what it is though.

Should I modify this code to populate the mapping_rules table using code (rather than importing it from an external .csv file) - ie easier to debug?

I've just run it again, and now I have a different error message:
Msg 7301, Level 16, State 2, Line 14
Cannot obtain the required interface ("IID_IColumnsInfo") from OLE DB provider "BULK" for linked server "(null)".