I have noticed the same issue. If I type xxxxxxx enter I don’t get what I’m looking for.
But interestingly if I type content:xxxxxxx I get the results expected. It appears on DTTG this is not working correctly when hitting enter since using content search does work.
While this isn’t a horrible thing (since search is possible), does make one wish there was a more friendly search (aka a drop down bar or something) with the command search operators rather than manual type on mobile which is not fast to do.