As mentioned, if you put Instant APs in the same network they will automatically form a cluster and synchronize configuration.
If you don't want the AP to do any clustering and manage it on its own, you can convert the AP to Standalone.
Disabling auto-join may not be enough as I expect the second AP to not bring up it's management interface as it finds there is a cluster running already (which it can't join).
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Herman Robers
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If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check
https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
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