As written in manual, for fast-forward to actually kick in there are a number of prerequisites which have to be fulfilled. One is “Bridge VLAN Filtering is disabled”, the other is “Bridge has only 2 running ports” and another one is “MAC address for the bridge matches with a MAC address from one of the bridge slave ports” (this one is not fulfilled if one follows rule #6 of The twelve Rules of Mikrotik Club).
So it’s very unlikely (but not impossible) to actually see fast-forward in action. Not in context of this thread.