firepower

[securitybeeline]

Hi i have a problem, after the connection rules to intercept files tab

analysis

file

file-events some names of the captured file is displayed normally but some like this 

=?UTF-8?B?0J/QnyAyMi0wMi0xNi0yLnBkZg==?=

or

*0*=UTF-8''%D1%81%D0%BA%D0%B0%D0%BD%D0%B8%D1%80%D0%BE%D0%B2%D0%B0;  filename*1*=%D0%BD%D0%B8%D0%B5%30%30%30%32%2E%70%64%66

what is the reason ?