Recently, I played with the tls-host fields in the rules. I noticed that the connections were half-fasttracked - meaning only one of the counters is increasing.

My setup is like this: The wired connections are untagged, the wifi between the routers is tagged and defined as AP-BRIDGE on the main (internet) router.

I initially thought this was related to the TLS processing - given the router needs to be able to see within the connection, so I removed the rules and rebooted the router. But still the same. Looking further, I noticed that one router (the internet one) fasttracks the connection one way, the other (the internal router) fasttracks the connections one way but the other way. For example, on the main (internet) router
While on the internal router
Both are running RouterOS 7.14.3. (edited, initially wrote 7.14.2)

Anyone else has seen that kind of behaviour?

Digging further, it seems that anything coming or going to a Wifi interface is not fasttracked. Question asked to the support.