I have one "hill" of gems inside my house and I never before had this problem, until some days ago: Now every time that I want to drop there a new gem I need to jump and drop it from the air.
I reported this issue when I noticed it. I found a trick meanwhile and managed to drop the ruby. I replied that on that same report. I also was told that this is a known issue.
Days had passed and I am still having this same problem now. I need to jump over that "hill" to drop the gem stone.
Maybe this info can be useful for people that are having this same problem.