Default [Q] Android 4.4.3/4.4.4 bug - Backing out of apps, opens recent application

When I flashed stock 4.4.3 update (kernel, radio and firmware) I thought maybe I've installed a bad ROM.
Every time I backed out of certain applications, the last application in the recent apps list (the one before the one I just backed out from) opened for a second and closed it self.

For example, I played Boom beach, sent it to background using HOME.
Then, I used App Stats, played around in some screens and then backed out of it -> Boom beach opened for a second and closed itself.

Then I installed the 4.4.4 update, and this still occurs...
This doesn't happen with every application... I can back out of most apps without any issue.

This never happened on 4.4.2 and lower.

It may be an app issue and not the system so I'd love a feedback from you guys before I contact the apps developers.

Am I the only one who experience this issue?
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