Keyword search works fine, some smart galleries do not

A few days ago, two of my smart galleries stopped working properly: they only show 2 or 3 pictures instead of dozens. Both have a single "include keyword" rule. I first thought that the issue was related to the keyword itself, as in both cases it spells with an accent: "rivière" (river) and "véhicule" (vehicle). But another smart gallery based on an accented keyword works fine ("fenêtre" for window). And querying from the keyword page works fine with any of these keywords. Thanks for your help!