I personally find it sooooo much more reliable than it used to be. It is still a problem occasionally, but I used to see the "you cannot swap weapons now" message almost constantly in Cyrodiil. It was my number one cause of ESO rage. It hasn't been that bad in months.
Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, the abyss gazes also into you. ~Friedrich Nietzsche
Know it happens constantly with Bow I use all 5 bow skills on bar and if any of the dots are still in effect you are stuck with a bow bar you can not swap.