mozilla weird emails
 

when I'm in Mozilla, I get sometimes weird emails

the subjects are fine, but the message looks like this.


QW5kcmUgRG11bWVubWRhYWwgdGVydWdiZWxsZW4u
IHR1bC4gMDI2LTM2MTg0MTkKCi0tIApWcm11bmR1bG1qa2UgZ3JvZXQsCgpNL
iBGYWF0cwp3d3cuZmFpcmdyb2VwLm5sCgo=

I think its a problem with some settings.
and in most cases it occurs when someone sends a PDF file.

but this happens occasionly