Jericho’s tile layout only hitting part of the backline, combined with the fact that she screams “only use me with MGs”, and the fact that you could just use a generic HG like P22 with MGs just fine and end up with pretty much the same result means she’s completely and utterly useless.
As such, Jericho is not recommended for use.
Full analysis
Reloads from non-MGs such as Nagant/M1895 Mod's Skill 2, Falcon, and HS.50 do not trigger Jericho's passive skill.
The passive skill also does not show any markers or indicators when it is activated, but the buff still applies normally.