Minor bugreport:
Since as long as I use EUI mod there are always plots that are not displaying yields, although they have yields. They are most often a big cluster of ~10x10 plots or so, there may be more than one of such a cluster, but most often it is only one. And depending on the zoom level and on the scroll level (if the cluster is in the middle of screen or on the edge) the yields do show or do not show.
Hopefully with this description you already know what might cause it. I confirmed this behaviour with the original EUI 1.29e without any mods and this does not happen with the original YieldIconManager.
It should be easy to reproduce when loading any singpleplayer map with big size and zoom/scroll over the whole map to find such a cluster (use a lua command or mod to explore the map). If you can't reproduce it, let me know and I will send you a savegame.
edit: ok you are right, it is no EUI issue, so most likely canot be fixed =/
And a vanilla game bug (that is also present and made worse in EUI) you might be interested in fixing:
When you have 2 cities quite near next to each other, so you can exchange their plots to be worked by the other city, the "switch-buttons" in the cityview do not show always properly. It happens that instead it shows the usual "empty citizen" button, which is quite confusing if you want to know which plot belongs to which city. If you click that empty citizen button it switches the plot to the other city, but without forcing a citizen to that plot. Only a second click will force a citizen to that plot. So the button is working as intended, but with wrong icon.
This is also easy to reproduce, simply load any game in advanced era to start with 2 settlers and choose shoshones as civ to have more land on settling. Settle them next to each other and you should see what I mean.
--> if you fix this, I recommend to also make these buttons (force-work and switch) to show even if the plot has no yield at all. Because in my current game (with EUI) I'm unable to switch a desert plot from one city to the other (because the desert currently has no yield, making the button do not appear). The city I want to switch it to has petra wonder built, so desert will gain yields there.
When I disable EUI I can switch the desert plot like described above, while with EUI for non of the 2 cities the desert plot is displaying any button, so partly this is a bug from EUI.