ePMP2000 with GPS sync in Edetect detecs AP at back as interferer

Have site with four ePMP AP's using GPS sync. If running eDetect AP1 detect the site behind it (180 deg) AP4 as an interferer.

AP1.JPG

One AP is set as front and the other as back in frequency reuse section. Both AP's are on same frequancy tracking 17 satelites. In my opinion this should not be possible if GPS sync functions as expected?

AP 1 does not detect AP4 though.

AP4.JPGAny suggestions?

eDetect runs during the Tx portion of the TDD frame. So it is entirely possible for back-to-back APs to hear each other when running eDetect. This does not impact GPS sync functionality. 

As for AP1 not detecting AP4, that's interesting. Are there any differences between the TX power setting of the APs?