There is a non-zero chance of Dapper treating character sequence in SQL query like ?something? as a pseudo-positional parameter inside of a literal, even if that is not an actual pseudo-positional parameter like in this example:

select '?this_is_my_string_data?' 

Note: it will not be considered a pseudo-positional parameter in case there are spaces:

select '?this is not pseudo-positional?' 

See github issue for more details.

To mitigate, you can split the string via concatenation:

select '?this_is' + 'my_string_data?'