Query bug since 10.0.31

I use a software called elevatedX. I recently ran a cpanel upgrade that upgraded MariaDB to 10.0.31. Since then the counting query in elevatedx runs but doesn't return any results. Prior to this everything was working find. ElevatedX has said its a bug in MariaDB. Here is what they told me. I apologize for lack of depth as I am not a dev.

This query works:

SELECT * FROM (totals) WHERE

TotalDate IN (select MAX(TotalDate) from totals WHERE TotalDate <= '2017-05-26');

This, however, does not:

SELECT * FROM (totals) WHERE

TotalDate IN (select MAX(TotalDate) from totals WHERE TotalDate <= '2017-05-26') OR TotalDate IS NULL;

This is a bug in your version of MariaDB. Please consult your host.

Any information on if this can be fixed or how I can downgrade would be appreciated.