That quest has some bugs. Specifically, if you have cleared out the weeds multiple times or tried to collect the amulet multiple times, you'll bug out the quest.
Both of those actions increment a status counter in the quest code, if you do each a single time the counter should end on a 4. However, the counter isn't reset if you leave the cave, so if you do either again you can get the counter to a higher number. Uffe's code specifically checks for '4', not '4 and higher', so if you made this mistake you'll have to load an earlier save.
It is also possible to just edit Uffe's code to check for 4 and higher, but I'm not sure how that could be done on Android.