When my character arrived at the stables in Orsinium (Wrothgar) to learn another Riding Lesson, Stable Master Dumoga was not displayed anywhere on the HUD. There are four other NPCs in the vicinity. Only one has an Interactive Prompt. When I use it, she tells my character that she is busy and not to bother her. However, eventually Dumoga's
voice can be heard, as she discusses the political situation with two of the other nearby NPCs, then states that they must all "get back to work".
For whatever it may be worth, I cannot recall seeing any of the three NPCs shown in the first screenshot below during previous visits, nor the fourth one which walks from below to the left end of the stables to do something. Previously, only Stable Master Dumoga was present when my character arrived, often facing a horse which she is brushing. (This suggests that there are two or more instances in which my character has been played, and they are not identical. There's your principal problem right there. In which instance does the bug occur, eh?)


After I used
/bug to create a Feedback report, the game client refused to accept it.
There was nothing else I could do other than to make another screenshot. EDIT: this problem has been solved by
@virtus753. The absence of Stablemaster Dumoga remains a mystery. ....

As the Feedback report states at the end, "Your game is becoming unplayable."
UPDATE: The screenshot below shows Stablemaster Dumoga -- as I have seen it before, among other alternatives in which only the NPC is present at the Stables.
Edited by Shadowshire on March 16, 2020 8:47PM --- Shadowshire .......... ESO Plus on PC NA with Windows 7 Pro SP1
nil carborundum illegitimi