Just wondering, have you ever used any other Linux OS-based miner images (BAMT, PIMP, SMOS, etc?) - because if not, I can tell you, that each and every one of these images and many others, come pre-configured with the developer's pool info that's up and mining for them as soon as you power on.  It is up to you to ensure that you change it after the OS is launched, and you may be mining for the dev in the first few minutes until you make the change.  Now, I understand you did make your appropriate pool changes, and it would appear Zen is overwriting that info periodically, so that's REALLY ODD - no excuse for that.. but Eric's response seems genuine so I would say why don't you give him the benefit of the doubt?  If you completely don't trust them anymore then just use a different mining distro that's not cloud-based.  There are other Pi options for blades, you may want to check out Starminer to start, there is a 'gridseed-blade' profile.  If you are experienced with Linux just run cgminer on raspbian.