The iPhone XS does not work well with the Mikrotik on 5GHz, the problem seems worst on 80MHz channels (Ceee) and the absolute worst is in the higher frequency channels. In general the iPhone XS does not work reliably with the Miktorik in the 5GHz, the only other access point I have to test with is an Asus RT-N56U that only supports 40MHz channels. The phone works "fine" on the Asus, but most of the time on the Mikrotik it fails to communicate.
It is odd that none of my other devices have this issue, including iPad Air, iPhone SE, iPhone 8, iPhone X....those all work fine. So it is either something about the Mikrotik is out of expectation or the iPhone XS is, but it is odd that the iPhone XS works fine on the ASUS as well.
/interface wireless set [ find default-name=wlan2 ] band=5ghz-onlyac disabled=no frequency=5765 mode=ap-bridge multicast-helper=full name="SSID 5GHz" security-profile="security-profile" ssid="SSID 5GHz" wireless-protocol=802.11 wmm-support=enabled wps-mode=disabled
Any pointers appreciated, I am hoping it is something stupid simple at this point.