cloned extender causes connection problems

so I purchased the above product about a year ago (11.5 months to be precise) and set it up to clone the existing router.
the thought was, from what was explained to me, that this way the connected device wouldnt necessarily have to switch access points, but the existing signal would just get extended.
about 6 months in, we started to have Wifi connection issues. On whim, I disconnected the extender. connections havent had an issue then.

This leads me to the conclusion that the problem lies with the ex8000.

Question is, how do I isolate and troubleshoot the ex8000 since it is now cloned to the router? Do I have to reset it to do it?