I have tried the educational game "learn to build towers". I pick the one with the yellow banners. 

I build it 5 blocks high and hit save.  When I go back in the top 3 blocks disappear

I try again, same result.  Also, blocks are difficult to destroy and sometimes disappear while building. 

This is on my kindle fire, but has happened once or twice on my phone too.  Please look into this.