Reproducible on 4.5, 4.6 and 5.x versions;
Tested on 4.5.5f1, 4.6.0f3, 4.6.5p3, 5.0.2p2, 5.1.0f2;

Repro steps:
1. open project "ParticleTest.zip";
2. open scene "test1" and hit "Play" button;
3. in scene view move the view field to the side of the main character. Rotate view field towards particle emission direction and when the parent object will be out of the view field, particles will also disappear.

Repro gif:
http://gyazo.com/d2812421bd59a694b942c52322addc4f