We are very happy users of MikroTik routers. Based on this experience, we did some tests with different MT 802.11ac APs. While doing this, we ran into some serious issues with DFS in 5Ghz channels 60 and above: MT 801.11ac APs randomly jump around on DFS 5Ghz channels claiming they sensed radar signals. Sometimes they stop working in 5Ghz completly, because they claim having sensed radars on all DFS channels.
We have Aruba and Zyxel APs running at the same location staying stable on the same DFS channels without sensing radar. While the MT APs in the same room switch DFS channels every few minutes because they sense radar signals. I took one of the MT APs to my remote vacation house, where the 5GHz band is completly free of noise. There it stays happily on DFS channels without ever sensing radars.
Seemingly MT DFS has issues in nosiy 5Ghz environments, but works fine in clean environments. As written above, no other brand AP ever sensed a radar signal in DFS mode at our location.
Beeing an Electrical Engineer with some understanding of RF electronics, my conclusion is MT APs wrongly detect other 5Ghz WiFi/Whatever signals as radar signals. This also matches DFS issues reported by other users in this forum.
Our environment is quite crowded on DFS-less 5Ghz channels. Not using DFS channels is not an option.