*** This description is outdated as of game version 1.3.2. If you still have the effect of missing landmarks/events with version 1.3.2 or newer, please post a screenshot, if possible, or the game number! ***
Currently there is a problem in the game client that will 'hide' one landmark/event in certain browser window sizes/aspect ratios. The problem is being worked on, but the following things you can do to
a) quickly check if you are potentially affected, and
b) thouroughly check if you are really affected, and
c) mitigate the issue.
A) Check if you are potentially affected:
The problem seems to occur only if both of the following conditions apply:
1) exactly eleven 'square' Kingdom cards (Young Witch + Bane card, or Looters including Ruin pile into the supply), and
2) no 'banner only' piles (non-supply card piles like Spoils, Madman or the new boons/hexes that don't have a picture, only a 'banner' with their name)
If both conditions are true and you use at least 2 events/landmarks, then it may happen that exactly one is located in a place that hides it from normal view.
B) What can you do if you are (potentially) affected?
3) Change the size of your browser window, including the aspect ratio (width to height).
4) Go from fullscreen to 'normal' and back to fullscreen.
Creating an extreme aspect ratio in 3) will usually do the trick, like making a very wide window with small height, or a window in portait format that is much taller than wide. If in these cases you don't see an additional event/landmark, then there is none.
C) If you find out that you are affected, you can
5) try to find a browser window size that shows all events/landmarks and is as acceptable to you as possible, or
6) if it is a landmark, you just remember that it is there and does its job, even if it has no visible on-screen implementation.