Gmail search behaving weired

Gmail search is behaving in a weired

way. For example if I have an email with Subject or Text “AMDSystemPrices”. Gmail sometimes does not search this and sometimes show this in suggestion [See screen shot].

Similarly IF I have an email with subject “PsyQ2010Files.zip” and I search keyword “PsyQ”, Gmail still not including email (marked with red box) in search results [see screen shot].

Even if I include complete subject “PsyQ2010Files”. It only suggest me my actual email

Obvious issue with this search is that search keyword are concatenated which could avoid it to be appeared in search results, but from user perspective it is a valid email text/subject. On the other hand I think Google will search such words but Gmail is not doing Why? Can anyone comment