Here are some small bugs that do not deserve their own thread.

The last game in the cheat database is not detected.
Open usrcheat.dat in r4cce, move the entry for your game to the very bottom of the list (or delete all other games), save, and Desmume's cheat importer won't see it.

"Enabled" cheats in database break Desmume's cheat parser.
Open usrcheat.dat in r4cce, select any code for your game, tick "Code Enabled" checkbox, save the .dat, and Desmume won't see cheats after that one. Flashcarts switch that flag in the database and it becomes annoying to use the same usrcheat.dat in Desmume and the flashcart's kernel.

Not a bug: "Import Advanscene DB" expects ADVANsCEne_RToolDS.xml file as distributed in ADVANsCEne_RToolDS.zip - someone on Desmume's github asked for it and I don't have an account there to post that. The link can be easily found on Google.