There's a normal piece of functionality that, once you're in a folder AquaMail will prevent you from Selecting the folder again to avoid wasting resources on showing something that's already there. This is all fine, well and good. However I think that this flag\status isn't being cleared when a Search is made.
To replicate: Pick a folder, any folder. Search for some email (anywhere, any criteria). Once search has completed, press the same folder to return to it. Doesn't work (it still thinks it's showing you that folder). E.g. Start in Inbox. Search for something. Press Inbox. Nothing happens - Inbox isn't shown and the search list remains.
Pick a folder, Search and then press another folder - the newly selected folder is correctly shown.
This only happens in Tablet mode (presumably because this flag\status is being cleared when the folder list is shown on the phone).
Pressing Back does allow a workaround in these circumstances, but it is intuitive to want to just press the folder again.
v1.2.5.0, Tested on Nexus 7 and Samsung GS3 (Phone and tablet mode)